diff --git a/android/app/build.gradle b/android/app/build.gradle
index 90858c7a..b4181680 100644
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -22,8 +22,8 @@ if (flutterVersionName == null) {
 }
 
 apply plugin: 'com.android.application'
-apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 apply plugin: 'kotlin-android'
+apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 def keystoreProperties = new Properties()
 def keystorePropertiesFile = rootProject.file('key.properties')
@@ -32,7 +32,11 @@ if (keystorePropertiesFile.exists()) {
 }
 
 android {
-    compileSdkVersion 29
+    compileSdkVersion 30
+
+    sourceSets {
+        main.java.srcDirs += 'src/main/kotlin'
+    }
 
     packagingOptions {
         exclude 'META-INF/proguard/androidx-annotations.pro'
@@ -45,7 +49,7 @@ android {
     defaultConfig {
         applicationId "inventree.inventree_app"
         minSdkVersion 25
-        targetSdkVersion 29
+        targetSdkVersion 30
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -78,7 +82,8 @@ dependencies {
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
-    androidTestImplementation 'com.android.support:multidex:1.0.0'
+    androidTestImplementation 'com.android.support:multidex:2.0.1'
+    implementation "androidx.core:core:1.5.0-rc01"
     implementation 'androidx.appcompat:appcompat:1.0.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 }
diff --git a/android/build.gradle b/android/build.gradle
index 7d9f14ca..13b686e5 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -1,6 +1,6 @@
 buildscript {
 
-    ext.kotlin_version = '1.4.21'
+    ext.kotlin_version = '1.5.10'
 
     repositories {
         google()
@@ -8,7 +8,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:4.1.0'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }
@@ -25,12 +25,7 @@ subprojects {
     project.buildDir = "${rootProject.buildDir}/${project.name}"
     project.evaluationDependsOn(':app')
     project.configurations.all {
-        resolutionStrategy.eachDependency { details ->
-            if (details.requested.group == 'androidx.core' &&
-                    !details.requested.name.contains('androidx')) {
-                details.useVersion "1.0.2"
-            }
-        }
+
     }
 }
 
diff --git a/android/gradle/wrapper/gradle-wrapper.properties b/android/gradle/wrapper/gradle-wrapper.properties
index 1e122a70..ca2bbd5d 100644
--- a/android/gradle/wrapper/gradle-wrapper.properties
+++ b/android/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-all.zip
\ No newline at end of file
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.9-all.zip
\ No newline at end of file
diff --git a/assets/release_notes.md b/assets/release_notes.md
index b5545c17..f8d1bc81 100644
--- a/assets/release_notes.md
+++ b/assets/release_notes.md
@@ -1,6 +1,14 @@
 ## InvenTree App Release Notes
 ---
 
+### 0.2.6 - July 2021
+---
+
+- Major code update with "null safety" features
+- Handle case of improperly formatted hostname
+- Multiple API bug fixes (mostly null references)
+- Updated translations
+
 ### 0.2.5 - June 2021
 ---
 
diff --git a/ios/Flutter/flutter_export_environment.sh b/ios/Flutter/flutter_export_environment.sh
index 45b3742b..4b84d6e6 100644
--- a/ios/Flutter/flutter_export_environment.sh
+++ b/ios/Flutter/flutter_export_environment.sh
@@ -1,13 +1,13 @@
 #!/bin/sh
 # This is a generated file; do not edit or check into version control.
-export "FLUTTER_ROOT=C:\flutter"
+export "FLUTTER_ROOT=c:\flutter"
 export "FLUTTER_APPLICATION_PATH=C:\inventree-app"
 export "COCOAPODS_PARALLEL_CODE_SIGN=true"
 export "FLUTTER_TARGET=lib\main.dart"
 export "FLUTTER_BUILD_DIR=build"
 export "SYMROOT=${SOURCE_ROOT}/../build\ios"
-export "FLUTTER_BUILD_NAME=0.1.5"
-export "FLUTTER_BUILD_NUMBER=9"
+export "FLUTTER_BUILD_NAME=0.2.6"
+export "FLUTTER_BUILD_NUMBER=14"
 export "DART_OBFUSCATION=false"
 export "TRACK_WIDGET_CREATION=false"
 export "TREE_SHAKE_ICONS=false"
diff --git a/lib/api.dart b/lib/api.dart
index 1d062680..6c335740 100644
--- a/lib/api.dart
+++ b/lib/api.dart
@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:InvenTree/inventree/sentry.dart';
 import 'package:InvenTree/user_profile.dart';
 import 'package:InvenTree/widget/snacks.dart';
 import 'package:flutter/cupertino.dart';
@@ -11,6 +12,7 @@ import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 import 'package:flutter_cache_manager/flutter_cache_manager.dart';
 import 'package:InvenTree/widget/dialogs.dart';
 import 'package:InvenTree/l10.dart';
+import 'package:InvenTree/inventree/sentry.dart';
 
 import 'package:http/http.dart' as http;
 import 'package:one_context/one_context.dart';
@@ -22,24 +24,31 @@ import 'package:one_context/one_context.dart';
  */
 class InvenTreeFileService extends FileService {
 
-  HttpClient _client;
+  HttpClient? _client = null;
 
-  InvenTreeFileService({HttpClient client, bool strictHttps = false}) {
+  InvenTreeFileService({HttpClient? client, bool strictHttps = false}) {
     _client = client ?? HttpClient();
-    _client.badCertificateCallback = (cert, host, port) {
-      print("BAD CERTIFICATE CALLBACK FOR IMAGE REQUEST");
-      return !strictHttps;
-    };
+
+    if (_client != null) {
+      _client?.badCertificateCallback = (cert, host, port) {
+        print("BAD CERTIFICATE CALLBACK FOR IMAGE REQUEST");
+        return !strictHttps;
+      };
+    }
   }
 
   @override
   Future<FileServiceResponse> get(String url,
-      {Map<String, String> headers = const {}}) async {
+      {Map<String, String>? headers}) async {
     final Uri resolved = Uri.base.resolve(url);
-    final HttpClientRequest req = await _client.getUrl(resolved);
-    headers?.forEach((key, value) {
-      req.headers.add(key, value);
-    });
+    final HttpClientRequest req = await _client!.getUrl(resolved);
+
+    if (headers != null) {
+      headers.forEach((key, value) {
+        req.headers.add(key, value);
+      });
+    }
+
     final HttpClientResponse httpResponse = await req.close();
     final http.StreamedResponse _response = http.StreamedResponse(
       httpResponse.timeout(Duration(seconds: 60)), httpResponse.statusCode,
@@ -101,7 +110,7 @@ class InvenTreeAPI {
 
   String makeUrl(String endpoint) => _makeUrl(endpoint);
 
-  UserProfile profile;
+  UserProfile? profile = null;
 
   Map<String, dynamic> roles = {};
 
@@ -171,15 +180,19 @@ class InvenTreeAPI {
    * - Request user token from the server
    * - Request user roles from the server
    */
-  Future<bool> _connect(BuildContext context) async {
+  Future<bool> _connect() async {
 
     if (profile == null) return false;
 
     var ctx = OneContext().context;
 
-    String address = profile.server.trim();
-    String username = profile.username.trim();
-    String password = profile.password.trim();
+    String address = profile?.server ?? "";
+    String username = profile?.username ?? "";
+    String password = profile?.password ?? "";
+
+    address = address.trim();
+    username = username.trim();
+    password = password.trim();
 
     if (address.isEmpty || username.isEmpty || password.isEmpty) {
       showSnackIcon(
@@ -202,7 +215,8 @@ class InvenTreeAPI {
 
     print("Connecting to ${apiUrl} -> username=${username}");
 
-    HttpClientResponse response;
+    HttpClientResponse? response;
+
     dynamic data;
 
     response = await getResponse("");
@@ -237,7 +251,7 @@ class InvenTreeAPI {
     instance = data['instance'] ?? '';
 
     // Default API version is 1 if not provided
-    _apiVersion = data['apiVersion'] as int ?? 1;
+    _apiVersion = (data['apiVersion'] ?? 1) as int;
 
     if (_apiVersion < _minApiVersion) {
 
@@ -315,7 +329,7 @@ class InvenTreeAPI {
 
   }
 
-  bool disconnectFromServer() {
+  void disconnectFromServer() {
     print("InvenTreeAPI().disconnectFromServer()");
 
     _connected = false;
@@ -324,7 +338,7 @@ class InvenTreeAPI {
     profile = null;
   }
 
-  Future<bool> connectToServer(BuildContext context) async {
+  Future<bool> connectToServer() async {
 
     // Ensure server is first disconnected
     disconnectFromServer();
@@ -345,7 +359,7 @@ class InvenTreeAPI {
 
     _connecting = true;
 
-    _connected = await _connect(context);
+    _connected = await _connect();
 
     print("_connect() returned result: ${_connected}");
 
@@ -411,7 +425,7 @@ class InvenTreeAPI {
 
 
   // Perform a PATCH request
-  Future<dynamic> patch(String url, {Map<String, String> body, int expectedStatusCode=200}) async {
+  Future<dynamic> patch(String url, {Map<String, String> body = const {}, int expectedStatusCode=200}) async {
     var _url = makeApiUrl(url);
     var _body = Map<String, String>();
 
@@ -433,7 +447,7 @@ class InvenTreeAPI {
     // Open a connection to the server
     HttpClientRequest request = await client.patchUrl(uri)
     .timeout(Duration(seconds: 10))
-    .catchError((error) {
+    .catchError((error, stackTrace) {
       print("PATCH request return error");
       print("URL: ${uri}");
       print("Error: ${error.toString()}");
@@ -446,12 +460,14 @@ class InvenTreeAPI {
           error.toString(),
         );
       } else if (error is TimeoutException) {
-        showTimeoutError(ctx);
+        showTimeoutError();
       } else {
         showServerError(
           L10().serverError,
           error.toString()
         );
+
+        sentryReportError(error, stackTrace);
       }
 
       return null;
@@ -462,7 +478,7 @@ class InvenTreeAPI {
       return null;
     }
 
-    var data = json.encode(body);
+    var data = json.encode(_body);
 
     // Set headers
     request.headers.set('Accept', 'application/json');
@@ -474,7 +490,7 @@ class InvenTreeAPI {
 
     HttpClientResponse response = await request.close()
     .timeout(Duration(seconds: 30))
-    .catchError((error) {
+    .catchError((error, stackTrace) {
       print("PATCH request returned error");
       print("URL: ${_url}");
       print("Error: ${error.toString()}");
@@ -487,29 +503,44 @@ class InvenTreeAPI {
             error.toString()
         );
       } else if (error is TimeoutException) {
-        showTimeoutError(ctx);
+        showTimeoutError();
       } else {
         showServerError(
             L10().serverError,
             error.toString()
         );
+
+        sentryReportError(error, stackTrace);
       }
 
       return null;
     });
 
-    if (response == null) {
-      print("null response from PATCH ${_url}");
-      return null;
-    }
+    var responseData = await responseToJson(response);
 
     if (response.statusCode != expectedStatusCode) {
       showStatusCodeError(response.statusCode);
+
+      print("PATCH to ${_url} returned status code ${response.statusCode}");
+      print("Data:");
+      print(responseData);
+
+      // Server error
+      if (response.statusCode >= 500) {
+        sentryReportMessage(
+            "Server error on PATCH request",
+            context: {
+              "url": _url,
+              "statusCode": "${response.statusCode}",
+              "response": responseData.toString(),
+              "request": body.toString(),
+            }
+        );
+      }
+
       return null;
     }
 
-    var responseData = await responseToJson(response);
-
     return responseData;
   }
 
@@ -517,7 +548,8 @@ class InvenTreeAPI {
    * Upload a file to the given URL
    */
   Future<http.StreamedResponse> uploadFile(String url, File f,
-      {String name = "attachment", String method="POST", Map<String, String> fields}) async {
+      {String name = "attachment", String method="POST", Map<String, String>? fields}) async {
+
     var _url = makeApiUrl(url);
 
     var request = http.MultipartRequest(method, Uri.parse(_url));
@@ -536,6 +568,21 @@ class InvenTreeAPI {
 
     var response = await request.send();
 
+    if (response.statusCode >= 500) {
+      // Server error
+      if (response.statusCode >= 500) {
+        sentryReportMessage(
+            "Server error on file upload",
+            context: {
+              "url": _url,
+              "statusCode": "${response.statusCode}",
+              "response": response.toString(),
+              "request": request.fields.toString(),
+            }
+        );
+      }
+    }
+
     return response;
   }
 
@@ -543,7 +590,8 @@ class InvenTreeAPI {
    * Perform a HTTP POST request
    * Returns a json object (or null if unsuccessful)
    */
-  Future<dynamic> post(String url, {Map<String, dynamic> body, int expectedStatusCode=201}) async {
+  Future<dynamic> post(String url, {Map<String, dynamic> body = const {}, int expectedStatusCode=201}) async {
+
     var _url = makeApiUrl(url);
 
     print("POST: ${_url} -> ${body.toString()}");
@@ -560,7 +608,7 @@ class InvenTreeAPI {
     // Open a connection to the server
     HttpClientRequest request = await client.postUrl(uri)
     .timeout(Duration(seconds: 10))
-    .catchError((error) {
+    .catchError((error, stackTrace) {
       print("POST request returned error");
       print("URL: ${uri}");
       print("Error: ${error.toString()}");
@@ -573,21 +621,19 @@ class InvenTreeAPI {
           error.toString()
         );
       } else if (error is TimeoutException) {
-        showTimeoutError(ctx);
+        showTimeoutError();
       } else {
         showServerError(
         L10().serverError,
         error.toString()
         );
+
+        sentryReportError(error, stackTrace);
       }
 
       return null;
     });
 
-    if (request == null) {
-      return null;
-    }
-
     var data = json.encode(body);
 
     // Set headers
@@ -602,7 +648,7 @@ class InvenTreeAPI {
 
     HttpClientResponse response = await request.close()
     .timeout(Duration(seconds: 30))
-    .catchError((error) {
+    .catchError((error, stackTrace) {
       print("POST request returned error");
       print("URL: ${_url}");
       print("Error: ${error.toString()}");
@@ -615,12 +661,14 @@ class InvenTreeAPI {
           error.toString()
         );
       } else if (error is TimeoutException) {
-        showTimeoutError(ctx);
+        showTimeoutError();
       } else {
         showServerError(
           L10().serverError,
           error.toString()
         );
+
+        sentryReportError(error, stackTrace);
       }
 
       return null;
@@ -631,13 +679,31 @@ class InvenTreeAPI {
       return null;
     }
 
+    var responseData = await responseToJson(response);
+
     if (response.statusCode != expectedStatusCode) {
       showStatusCodeError(response.statusCode);
+
+      print("POST to ${_url} returned status code ${response.statusCode}");
+      print("Data:");
+      print(responseData);
+
+      // Server error
+      if (response.statusCode >= 500) {
+        sentryReportMessage(
+          "Server error on POST request",
+          context: {
+            "url": _url,
+            "statusCode": "${response.statusCode}",
+            "response": responseData.toString(),
+            "request": body.toString(),
+          }
+        );
+      }
+
       return null;
     }
 
-    var responseData = await responseToJson(response);
-
     return responseData;
   }
 
@@ -674,13 +740,13 @@ class InvenTreeAPI {
    * and return the Response object
    * (or null if the request fails)
    */
-  Future<HttpClientResponse> getResponse(String url, {Map<String, String> params}) async {
+  Future<HttpClientResponse?> getResponse(String url, {Map<String, String> params = const {}}) async {
     var _url = makeApiUrl(url);
 
     print("GET: ${_url}");
 
     // If query parameters are supplied, form a query string
-    if (params != null && params.isNotEmpty) {
+    if (params.isNotEmpty) {
       String query = '?';
 
       params.forEach((K, V) => query += K + '=' + V + '&');
@@ -695,7 +761,12 @@ class InvenTreeAPI {
 
     var client = createClient(true);
 
-    final uri = Uri.parse(_url);
+    Uri? uri = Uri.tryParse(_url);
+
+    if (uri == null) {
+      showServerError(L10().invalidHost, L10().invalidHostDetails);
+      return null;
+    }
 
     // Check for invalid host
     if (uri.host.isEmpty) {
@@ -703,32 +774,60 @@ class InvenTreeAPI {
       return null;
     }
 
-    // Open a connection
-    HttpClientRequest request = await client.getUrl(uri)
-        .timeout(Duration(seconds: 10))
-        .catchError((error) {
-      print("GET request returned error");
-      print("URL: ${uri}");
-      print("Error: ${error.toString()}");
+    HttpClientRequest? request;
 
-      var ctx = OneContext().context;
+    try {
+      // Open a connection
+      request = await client.getUrl(uri)
+          .timeout(Duration(seconds: 10))
+          .catchError((error, stackTrace) {
+        print("GET request returned error");
+        print("URL: ${uri}");
+        print("Error: ${error.toString()}");
 
-      if (error is SocketException) {
+        var ctx = OneContext().context;
+
+        if (error is SocketException) {
+          showServerError(
+              L10().connectionRefused,
+              error.toString()
+          );
+        } else if (error is TimeoutException) {
+          showTimeoutError();
+        } else {
+          showServerError(
+              L10().serverError,
+              error.toString()
+          );
+
+          sentryReportError(error, stackTrace);
+        }
+
+        return null;
+      });
+    } catch (error, stackTrace) {
+      if (error is FormatException) {
+        showServerError(
+          L10().invalidHost,
+          L10().invalidHostDetails)
+        ;
+      } else if (error is SocketException) {
         showServerError(
             L10().connectionRefused,
             error.toString()
         );
-      } else if (error is TimeoutException) {
-        showTimeoutError(ctx);
       } else {
         showServerError(
-            L10().serverError,
-            error.toString()
+          L10().serverError,
+          error.toString()
         );
+        
+        // Report to sentry
+        sentryReportError(error, stackTrace);
       }
 
       return null;
-    });
+    }
 
     if (request == null) {
       return null;
@@ -740,7 +839,7 @@ class InvenTreeAPI {
 
     HttpClientResponse response = await request.close()
         .timeout(Duration(seconds: 10))
-        .catchError((error) {
+        .catchError((error, stackTrace) {
       print("GET request returned error");
       print("URL: ${_url}");
       print("Error: ${error.toString()}");
@@ -753,12 +852,14 @@ class InvenTreeAPI {
             error.toString()
         );
       } else if (error is TimeoutException) {
-        showTimeoutError(ctx);
+        showTimeoutError();
       } else {
         showServerError(
             L10().serverError,
             error.toString()
         );
+
+        sentryReportError(error, stackTrace);
       }
 
       return null;
@@ -769,10 +870,6 @@ class InvenTreeAPI {
 
   dynamic responseToJson(HttpClientResponse response) async {
 
-    if (response == null) {
-      return null;
-    }
-
     String body = await response.transform(utf8.decoder).join();
 
     try {
@@ -797,7 +894,7 @@ class InvenTreeAPI {
    * Perform a HTTP GET request
    * Returns a json object (or null if did not complete)
    */
-  Future<dynamic> get(String url, {Map<String, String> params, int expectedStatusCode=200}) async {
+  Future<dynamic> get(String url, {Map<String, String> params = const {}, int expectedStatusCode=200}) async {
 
     var response = await getResponse(url, params: params);
 
@@ -807,15 +904,29 @@ class InvenTreeAPI {
       return null;
     }
 
+    var responseData = await responseToJson(response);
+
     // Check the status code of the response
     if (response.statusCode != expectedStatusCode) {
       showStatusCodeError(response.statusCode);
+
+      // Server error
+      if (response.statusCode >= 500) {
+        sentryReportMessage(
+            "Server error on GET request",
+            context: {
+              "url": url,
+              "statusCode": "${response.statusCode}",
+              "response": responseData.toString(),
+              "params": params.toString(),
+            }
+        );
+      }
+
       return null;
     }
 
-    var data = await responseToJson(response);
-
-    return data;
+    return responseData;
   }
 
   Map<String, String> defaultHeaders() {
@@ -836,7 +947,7 @@ class InvenTreeAPI {
     if (_token.isNotEmpty) {
       return "Token $_token";
     } else if (profile != null) {
-      return "Basic " + base64Encode(utf8.encode('${profile.username}:${profile.password}'));
+      return "Basic " + base64Encode(utf8.encode('${profile?.username}:${profile?.password}'));
     } else {
       return "";
     }
@@ -846,13 +957,11 @@ class InvenTreeAPI {
 
   static String get staticThumb => "/static/img/blank_image.thumbnail.png";
 
-
-
   /**
    * Load image from the InvenTree server,
    * or from local cache (if it has been cached!)
    */
-  CachedNetworkImage getImage(String imageUrl, {double height, double width}) {
+  CachedNetworkImage getImage(String imageUrl, {double? height, double? width}) {
     if (imageUrl.isEmpty) {
       imageUrl = staticImage;
     }
diff --git a/lib/barcode.dart b/lib/barcode.dart
index 2f7a79ea..e0dbbf4b 100644
--- a/lib/barcode.dart
+++ b/lib/barcode.dart
@@ -35,8 +35,8 @@ class BarcodeHandler {
 
     BarcodeHandler();
 
-    QRViewController _controller;
-    BuildContext _context;
+    QRViewController? _controller;
+    BuildContext? _context;
 
     void successTone() async {
 
@@ -58,12 +58,12 @@ class BarcodeHandler {
       }
     }
 
-    Future<void> onBarcodeMatched(Map<String, dynamic> data) {
+    Future<void> onBarcodeMatched(Map<String, dynamic> data) async {
       // Called when the server "matches" a barcode
       // Override this function
     }
 
-    Future<void> onBarcodeUnknown(Map<String, dynamic> data) {
+    Future<void> onBarcodeUnknown(Map<String, dynamic> data) async {
       // Called when the server does not know about a barcode
       // Override this function
 
@@ -76,17 +76,17 @@ class BarcodeHandler {
       );
     }
 
-    Future<void> onBarcodeUnhandled(Map<String, dynamic> data) {
+    Future<void> onBarcodeUnhandled(Map<String, dynamic> data) async {
 
       failureTone();
 
       // Called when the server returns an unhandled response
       showServerError(L10().responseUnknown, data.toString());
 
-      _controller.resumeCamera();
+      _controller?.resumeCamera();
     }
 
-    Future<void> processBarcode(BuildContext context, QRViewController _controller, String barcode, {String url = "barcode/"}) async {
+    Future<void> processBarcode(BuildContext? context, QRViewController? _controller, String barcode, {String url = "barcode/"}) async {
       this._context = context;
       this._controller = _controller;
 
@@ -105,13 +105,13 @@ class BarcodeHandler {
       }
 
       if (data.containsKey('error')) {
-        _controller.resumeCamera();
+        _controller?.resumeCamera();
         onBarcodeUnknown(data);
       } else if (data.containsKey('success')) {
-        _controller.resumeCamera();
+        _controller?.resumeCamera();
         onBarcodeMatched(data);
       } else {
-        _controller.resumeCamera();
+        _controller?.resumeCamera();
         onBarcodeUnhandled(data);
       }
     }
@@ -128,7 +128,7 @@ class BarcodeScanHandler extends BarcodeHandler {
   String getOverlayText(BuildContext context) => L10().barcodeScanGeneral;
 
   @override
-  Future<void> onBarcodeUnknown(Map<String, dynamic> data) {
+  Future<void> onBarcodeUnknown(Map<String, dynamic> data) async {
 
     failureTone();
 
@@ -140,8 +140,9 @@ class BarcodeScanHandler extends BarcodeHandler {
   }
 
   @override
-  Future<void> onBarcodeMatched(Map<String, dynamic> data) {
-    int pk;
+  Future<void> onBarcodeMatched(Map<String, dynamic> data) async {
+
+    int pk = -1;
 
     print("Handle barcode:");
     print(data);
@@ -149,16 +150,21 @@ class BarcodeScanHandler extends BarcodeHandler {
     // A stocklocation has been passed?
     if (data.containsKey('stocklocation')) {
 
-      pk = data['stocklocation']['pk'] as int ?? null;
+      pk = (data['stocklocation']?['pk'] ?? -1) as int;
 
-      if (pk != null) {
+      if (pk > 0) {
 
         successTone();
 
-        InvenTreeStockLocation().get(_context, pk).then((var loc) {
+        InvenTreeStockLocation().get(pk).then((var loc) {
           if (loc is InvenTreeStockLocation) {
-            Navigator.of(_context).pop();
-            Navigator.push(_context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(loc)));
+
+            var _ctx = _context;
+
+            if (_ctx != null) {
+              Navigator.of(_ctx).pop();
+              Navigator.push(_ctx, MaterialPageRoute(builder: (context) => LocationDisplayWidget(loc)));
+            }
           }
         });
       } else {
@@ -173,15 +179,24 @@ class BarcodeScanHandler extends BarcodeHandler {
 
     } else if (data.containsKey('stockitem')) {
 
-      pk = data['stockitem']['pk'] as int ?? null;
+      pk = (data['stockitem']?['pk'] ?? -1) as int;
 
-      if (pk != null) {
+      if (pk > 0) {
 
         successTone();
 
-        InvenTreeStockItem().get(_context, pk).then((var item) {
-          Navigator.of(_context).pop();
-          Navigator.push(_context, MaterialPageRoute(builder: (context) => StockDetailWidget(item)));
+        InvenTreeStockItem().get(pk).then((var item) {
+
+          var _ctx = _context;
+
+          if (_ctx != null) {
+            // Dispose of the barcode scanner
+            Navigator.of(_ctx).pop();
+
+            if (item is InvenTreeStockItem) {
+              Navigator.push(_ctx, MaterialPageRoute(builder: (context) => StockDetailWidget(item)));
+            }
+          }
         });
       } else {
 
@@ -194,15 +209,24 @@ class BarcodeScanHandler extends BarcodeHandler {
       }
     } else if (data.containsKey('part')) {
 
-      pk = data['part']['pk'] as int ?? null;
+      pk = (data['part']?['pk'] ?? -1) as int;
 
-      if (pk != null) {
+      if (pk > 0) {
 
         successTone();
 
-        InvenTreePart().get(_context, pk).then((var part) {
-          Navigator.of(_context).pop();
-          Navigator.push(_context, MaterialPageRoute(builder: (context) => PartDetailWidget(part)));
+        InvenTreePart().get(pk).then((var part) {
+
+          var _ctx = _context;
+
+          if (_ctx != null) {
+            // Dismiss the barcode scanner
+            Navigator.of(_ctx).pop();
+
+            if (part is InvenTreePart) {
+              Navigator.push(_ctx, MaterialPageRoute(builder: (context) => PartDetailWidget(part)));
+            }
+          }
         });
       } else {
 
@@ -221,8 +245,10 @@ class BarcodeScanHandler extends BarcodeHandler {
         L10().barcodeUnknown,
         success: false,
         onAction: () {
-          showDialog(
-              context: _context,
+
+          var _ctx = OneContext().context;
+
+          OneContext().showDialog(
               builder: (BuildContext context) => SimpleDialog(
                 title: Text(L10().unknownResponse),
                 children: <Widget>[
@@ -257,7 +283,7 @@ class StockItemBarcodeAssignmentHandler extends BarcodeHandler {
   String getOverlayText(BuildContext context) => L10().barcodeScanAssign;
 
   @override
-  Future<void> onBarcodeMatched(Map<String, dynamic> data) {
+  Future<void> onBarcodeMatched(Map<String, dynamic> data) async {
 
     failureTone();
 
@@ -270,7 +296,7 @@ class StockItemBarcodeAssignmentHandler extends BarcodeHandler {
   }
 
   @override
-  Future<void> onBarcodeUnknown(Map<String, dynamic> data) {
+  Future<void> onBarcodeUnknown(Map<String, dynamic> data) async {
     // If the barcode is unknown, we *can* assign it to the stock item!
 
     if (!data.containsKey("hash")) {
@@ -282,7 +308,6 @@ class StockItemBarcodeAssignmentHandler extends BarcodeHandler {
 
       // Send the 'hash' code as the UID for the stock item
       item.update(
-        _context,
         values: {
           "uid": data['hash'],
         }
@@ -292,8 +317,13 @@ class StockItemBarcodeAssignmentHandler extends BarcodeHandler {
           failureTone();
 
           // Close the barcode scanner
-          _controller.dispose();
-          Navigator.of(_context).pop();
+          _controller?.dispose();
+
+          var _ctx = (_context);
+
+          if (_ctx != null) {
+            Navigator.of(_ctx).pop();
+          }
 
           showSnackIcon(
             L10().barcodeAssigned,
@@ -350,8 +380,13 @@ class StockItemScanIntoLocationHandler extends BarcodeHandler {
         successTone();
 
         // Close the scanner
-        _controller.dispose();
-        Navigator.of(_context).pop();
+        _controller?.dispose();
+
+        var _ctx = _context;
+
+        if (_ctx != null) {
+          Navigator.of(_ctx).pop();
+        }
 
         showSnackIcon(
           L10().barcodeScanIntoLocationSuccess,
@@ -403,7 +438,7 @@ class StockLocationScanInItemsHandler extends BarcodeHandler {
 
       int item_id = data['stockitem']['pk'] as int;
 
-      final InvenTreeStockItem item = await InvenTreeStockItem().get(_context, item_id);
+      final InvenTreeStockItem? item = await InvenTreeStockItem().get(item_id) as InvenTreeStockItem;
 
       if (item == null) {
 
@@ -459,7 +494,7 @@ class InvenTreeQRView extends StatefulWidget {
 
   final BarcodeHandler _handler;
 
-  InvenTreeQRView(this._handler, {Key key}) : super(key: key);
+  InvenTreeQRView(this._handler, {Key? key}) : super(key: key);
 
   @override
   State<StatefulWidget> createState() => _QRViewState(_handler);
@@ -468,11 +503,11 @@ class InvenTreeQRView extends StatefulWidget {
 
 class _QRViewState extends State<InvenTreeQRView> {
 
-  QRViewController _controller;
+  QRViewController? _controller;
 
   final BarcodeHandler _handler;
 
-  BuildContext context;
+  BuildContext? _context;
 
   // In order to get hot reload to work we need to pause the camera if the platform
   // is android, or resume the camera if the platform is iOS.
@@ -480,9 +515,9 @@ class _QRViewState extends State<InvenTreeQRView> {
   void reassemble() {
     super.reassemble();
     if (Platform.isAndroid) {
-      _controller.pauseCamera();
+      _controller?.pauseCamera();
     } else if (Platform.isIOS) {
-      _controller.resumeCamera();
+      _controller?.resumeCamera();
     }
   }
 
@@ -494,7 +529,7 @@ class _QRViewState extends State<InvenTreeQRView> {
     _controller = controller;
     controller.scannedDataStream.listen((barcode) {
       _controller?.pauseCamera();
-      _handler.processBarcode(context, _controller, barcode.code);
+      _handler.processBarcode(_context, _controller, barcode.code);
     });
   }
 
@@ -508,7 +543,7 @@ class _QRViewState extends State<InvenTreeQRView> {
   Widget build(BuildContext context) {
 
     // Save the context for later on!
-    this.context = context;
+    this._context = context;
 
     return Scaffold(
         body: Stack(
diff --git a/lib/inventree/model.dart b/lib/inventree/model.dart
index 0d269c4d..678739a6 100644
--- a/lib/inventree/model.dart
+++ b/lib/inventree/model.dart
@@ -33,7 +33,7 @@ class InvenTreePageResponse {
 
   int get count => _count;
 
-  int get length => results?.length ?? 0;
+  int get length => results.length;
 
   List<InvenTreeModel> results = [];
 }
@@ -91,16 +91,16 @@ class InvenTreeModel {
 
   }
 
-  int get pk => jsondata['pk'] ?? -1;
+  int get pk => (jsondata['pk'] ?? -1) as int;
 
   // Some common accessors
   String get name => jsondata['name'] ?? '';
 
   String get description => jsondata['description'] ?? '';
 
-  String get notes => jsondata['notes'] as String ?? '';
+  String get notes => jsondata['notes'] ?? '';
 
-  int get parentId => jsondata['parent'] as int ?? -1;
+  int get parentId => (jsondata['parent'] ?? -1) as int;
 
   // Legacy API provided external link as "URL", while newer API uses "link"
   String get link => jsondata['link'] ?? jsondata['URL'] ?? '';
@@ -127,7 +127,7 @@ class InvenTreeModel {
     }
   }
 
-  String get keywords => jsondata['keywords'] as String ?? '';
+  String get keywords => jsondata['keywords'] ?? '';
 
   // Create a new object from JSON data (not a constructor!)
   InvenTreeModel createFromJson(Map<String, dynamic> json) {
@@ -142,15 +142,11 @@ class InvenTreeModel {
 
 
   // Search this Model type in the database
-  Future<List<InvenTreeModel>> search(BuildContext context, String searchTerm, {Map<String, String> filters}) async {
-
-    if (filters == null) {
-      filters = {};
-    }
+  Future<List<InvenTreeModel>> search(BuildContext context, String searchTerm, {Map<String, String> filters = const {}}) async {
 
     filters["search"] = searchTerm;
 
-    final results = list(context, filters: filters);
+    final results = list(filters: filters);
 
     return results;
 
@@ -164,7 +160,7 @@ class InvenTreeModel {
   /*
    * Reload this object, by requesting data from the server
    */
-  Future<bool> reload(BuildContext context) async {
+  Future<bool> reload() async {
 
     var response = await api.get(url, params: defaultGetFilters());
     
@@ -178,7 +174,7 @@ class InvenTreeModel {
   }
 
   // POST data to update the model
-  Future<bool> update(BuildContext context, {Map<String, String> values}) async {
+  Future<bool> update({Map<String, String> values = const {}}) async {
 
     var addr = path.join(URL, pk.toString());
 
@@ -198,29 +194,27 @@ class InvenTreeModel {
   }
 
   // Return the detail view for the associated pk
-  Future<InvenTreeModel> get(BuildContext context, int pk, {Map<String, String> filters}) async {
+  Future<InvenTreeModel?> get(int pk, {Map<String, String> filters = const {}}) async {
 
     // TODO - Add "timeout"
     // TODO - Add error catching
 
-    var addr = path.join(URL, pk.toString());
+    var url = path.join(URL, pk.toString());
 
-    if (!addr.endsWith("/")) {
-      addr += "/";
+    if (!url.endsWith("/")) {
+      url += "/";
     }
 
     var params = defaultGetFilters();
 
-    if (filters != null) {
-      // Override any default values
-      for (String key in filters.keys) {
-        params[key] = filters[key];
-      }
+    // Override any default values
+    for (String key in filters.keys) {
+      params[key] = filters[key] ?? '';
     }
 
-    print("GET: $addr ${params.toString()}");
+    print("GET: $url ${params.toString()}");
 
-    var response = await api.get(addr, params: params);
+    var response = await api.get(url, params: params);
 
     if (response == null) {
       return null;
@@ -229,7 +223,7 @@ class InvenTreeModel {
     return createFromJson(response);
   }
 
-  Future<InvenTreeModel> create(BuildContext context, Map<String, dynamic> data) async {
+  Future<InvenTreeModel?> create(Map<String, dynamic> data) async {
 
     print("CREATE: ${URL} ${data.toString()}");
 
@@ -241,8 +235,6 @@ class InvenTreeModel {
       data.remove('id');
     }
 
-    InvenTreeModel _model;
-
     var response = await api.post(URL, body: data);
 
     if (response == null) {
@@ -252,13 +244,11 @@ class InvenTreeModel {
     return createFromJson(response);
   }
 
-  Future<InvenTreePageResponse> listPaginated(int limit, int offset, {Map<String, String> filters}) async {
+  Future<InvenTreePageResponse?> listPaginated(int limit, int offset, {Map<String, String> filters = const {}}) async {
     var params = defaultListFilters();
 
-    if (filters != null) {
-      for (String key in filters.keys) {
-        params[key] = filters[key];
-      }
+    for (String key in filters.keys) {
+      params[key] = filters[key] ?? '';
     }
 
     params["limit"] = "${limit}";
@@ -285,25 +275,17 @@ class InvenTreeModel {
        return page;
 
     } else {
-      // Inavlid response
-      print("Invalid!");
       return null;
     }
   }
 
   // Return list of objects from the database, with optional filters
-  Future<List<InvenTreeModel>> list(BuildContext context, {Map<String, String> filters}) async {
-
-    if (filters == null) {
-      filters = {};
-    }
+  Future<List<InvenTreeModel>> list({Map<String, String> filters = const {}}) async {
 
     var params = defaultListFilters();
 
-    if (filters != null) {
-      for (String key in filters.keys) {
-        params[key] = filters[key];
-      }
+    for (String key in filters.keys) {
+      params[key] = filters[key] ?? '';
     }
 
     print("LIST: $URL ${params.toString()}");
@@ -311,7 +293,7 @@ class InvenTreeModel {
     var response = await api.get(URL, params: params);
 
     // A list of "InvenTreeModel" items
-    List<InvenTreeModel> results = new List<InvenTreeModel>();
+    List<InvenTreeModel> results = [];
 
     if (response == null) {
       return results;
diff --git a/lib/inventree/part.dart b/lib/inventree/part.dart
index 82c44a8b..4cc4b127 100644
--- a/lib/inventree/part.dart
+++ b/lib/inventree/part.dart
@@ -100,10 +100,11 @@ class InvenTreePartTestTemplate extends InvenTreeModel {
   }
 
   bool passFailStatus() {
+
     var result = latestResult();
 
     if (result == null) {
-      return null;
+      return false;
     }
 
     return result.result;
@@ -113,7 +114,7 @@ class InvenTreePartTestTemplate extends InvenTreeModel {
   List<InvenTreeStockItemTestResult> results = [];
 
   // Return the most recent test result recorded against this template
-  InvenTreeStockItemTestResult latestResult() {
+  InvenTreeStockItemTestResult? latestResult() {
     if (results.isEmpty) {
       return null;
     }
@@ -143,12 +144,12 @@ class InvenTreePart extends InvenTreeModel {
   @override
   Map<String, String> defaultGetFilters() {
     return {
-      "category_detail": "1",   // Include category detail information
+      "category_detail": "true",   // Include category detail information
     };
   }
 
   // Cached list of stock items
-  List<InvenTreeStockItem> stockItems = List<InvenTreeStockItem>();
+  List<InvenTreeStockItem> stockItems = [];
 
   int get stockItemCount => stockItems.length;
 
@@ -156,7 +157,6 @@ class InvenTreePart extends InvenTreeModel {
   Future<void> getStockItems(BuildContext context, {bool showDialog=false}) async {
 
     await InvenTreeStockItem().list(
-      context,
       filters: {
         "part": "${pk}",
         "in_stock": "true",
@@ -172,18 +172,17 @@ class InvenTreePart extends InvenTreeModel {
     });
   }
 
-  int get supplier_count => jsondata['suppliers'] as int ?? 0;
+  int get supplier_count => (jsondata['suppliers'] ?? 0) as int;
 
   // Cached list of test templates
-  List<InvenTreePartTestTemplate> testingTemplates = List<InvenTreePartTestTemplate>();
+  List<InvenTreePartTestTemplate> testingTemplates = [];
 
   int get testTemplateCount => testingTemplates.length;
 
   // Request test templates from the serve
-  Future<void> getTestTemplates(BuildContext context, {bool showDialog=false}) async {
+  Future<void> getTestTemplates({bool showDialog=false}) async {
 
     InvenTreePartTestTemplate().list(
-      context,
       filters: {
         "part": "${pk}",
       },
@@ -200,10 +199,10 @@ class InvenTreePart extends InvenTreeModel {
   }
 
     // Get the number of stock on order for this Part
-    double get onOrder => double.tryParse(jsondata['ordering'].toString() ?? '0');
+    double get onOrder => double.tryParse(jsondata['ordering'].toString()) ?? 0;
 
     // Get the stock count for this Part
-    double get inStock => double.tryParse(jsondata['in_stock'].toString() ?? '0');
+    double get inStock => double.tryParse(jsondata['in_stock'].toString()) ?? 0;
 
     String get inStockString {
 
@@ -215,51 +214,55 @@ class InvenTreePart extends InvenTreeModel {
     }
 
     // Get the number of units being build for this Part
-    double get building => double.tryParse(jsondata['building'].toString() ?? '0');
+    double get building => double.tryParse(jsondata['building'].toString()) ?? 0;
 
     // Get the number of BOM items in this Part (if it is an assembly)
-    int get bomItemCount => jsondata['bom_items'] as int ?? 0;
+    int get bomItemCount => (jsondata['bom_items'] ?? 0) as int;
 
     // Get the number of BOMs this Part is used in (if it is a component)
-    int get usedInCount => jsondata['used_in'] as int ?? 0;
+    int get usedInCount => (jsondata['used_in'] ?? 0) as int;
 
-    bool get isAssembly => jsondata['assembly'] ?? false;
+    bool get isAssembly => (jsondata['assembly'] ?? false) as bool;
 
-    bool get isComponent => jsondata['component'] ?? false;
+    bool get isComponent => (jsondata['component'] ?? false) as bool;
 
-    bool get isPurchaseable => jsondata['purchaseable'] ?? false;
+    bool get isPurchaseable => (jsondata['purchaseable'] ?? false) as bool;
 
-    bool get isSalable => jsondata['salable'] ?? false;
+    bool get isSalable => (jsondata['salable'] ?? false) as bool;
 
-    bool get isActive => jsondata['active'] ?? false;
+    bool get isActive => (jsondata['active'] ?? false) as bool;
 
-    bool get isVirtual => jsondata['virtual'] ?? false;
+    bool get isVirtual => (jsondata['virtual'] ?? false) as bool;
 
-    bool get isTrackable => jsondata['trackable'] ?? false;
+    bool get isTrackable => (jsondata['trackable'] ?? false) as bool;
 
     // Get the IPN (internal part number) for the Part instance
-    String get IPN => jsondata['IPN'] as String ?? '';
+    String get IPN => jsondata['IPN'] ?? '';
 
     // Get the revision string for the Part instance
-    String get revision => jsondata['revision'] as String ?? '';
+    String get revision => jsondata['revision'] ?? '';
 
     // Get the category ID for the Part instance (or 'null' if does not exist)
-    int get categoryId => jsondata['category'] as int ?? null;
+    int get categoryId => (jsondata['category'] ?? -1) as int;
 
     // Get the category name for the Part instance
     String get categoryName {
-      if (categoryId == null) return '';
+      // Inavlid category ID
+      if (categoryId <= 0) return '';
+
       if (!jsondata.containsKey('category_detail')) return '';
 
-      return jsondata['category_detail']['name'] as String ?? '';
+      return jsondata['category_detail']?['name'] ?? '';
     }
 
     // Get the category description for the Part instance
     String get categoryDescription {
-      if (categoryId == null) return '';
+      // Invalid category ID
+      if (categoryId <= 0) return '';
+
       if (!jsondata.containsKey('category_detail')) return '';
 
-      return jsondata['category_detail']['description'] as String ?? '';
+      return jsondata['category_detail']?['description'] ?? '';
     }
     // Get the image URL for the Part instance
     String get _image  => jsondata['image'] ?? '';
@@ -274,7 +277,7 @@ class InvenTreePart extends InvenTreeModel {
 
       if (fn.isNotEmpty) return fn;
 
-      List<String> elements = List<String>();
+      List<String> elements = [];
 
       if (IPN.isNotEmpty) elements.add(IPN);
 
@@ -324,7 +327,7 @@ class InvenTreePart extends InvenTreeModel {
     }
 
     // Return the "starred" status of this part
-    bool get starred => jsondata['starred'] as bool ?? false;
+    bool get starred => (jsondata['starred'] ?? false) as bool;
 
     InvenTreePart() : super();
 
diff --git a/lib/inventree/sentry.dart b/lib/inventree/sentry.dart
index 65a997a0..da729e0a 100644
--- a/lib/inventree/sentry.dart
+++ b/lib/inventree/sentry.dart
@@ -84,6 +84,40 @@ bool isInDebugMode() {
   return inDebugMode;
 }
 
+Future<bool> sentryReportMessage(String message, {Map<String, String>? context}) async {
+
+  final server_info = getServerInfo();
+  final app_info = await getAppInfo();
+  final device_info = await getDeviceInfo();
+
+  print("Sending user message to Sentry: ${message}");
+
+  if (isInDebugMode()) {
+
+    print('----- In dev mode. Not sending message to Sentry.io -----');
+    return true;
+  }
+
+  Sentry.configureScope((scope) {
+    scope.setExtra("server", server_info);
+    scope.setExtra("app", app_info);
+    scope.setExtra("device", device_info);
+
+    if (context != null) {
+      scope.setExtra("context", context);
+    }
+  });
+
+  final sentryId = await Sentry.captureMessage(message).catchError((error) {
+    print("Error uploading sentry messages...");
+    print(error);
+    return null;
+  });
+
+  return sentryId != null;
+}
+
+
 Future<void> sentryReportError(dynamic error, dynamic stackTrace) async {
 
   print('----- Sentry Intercepted error: $error -----');
@@ -115,27 +149,3 @@ Future<void> sentryReportError(dynamic error, dynamic stackTrace) async {
     print("Uploaded information to Sentry.io : ${response.toString()}");
   });
 }
-
-
-Future<bool> sentryReportMessage(String message) async {
-
-  final server_info = getServerInfo();
-  final app_info = await getAppInfo();
-  final device_info = await getDeviceInfo();
-
-  print("Sending user message to Sentry");
-
-  Sentry.configureScope((scope) {
-    scope.setExtra("server", server_info);
-    scope.setExtra("app", app_info);
-    scope.setExtra("device", device_info);
-  });
-
-  final sentryId = await Sentry.captureMessage(message).catchError((error) {
-    print("Error uploading sentry messages...");
-    print(error);
-    return null;
-  });
-
-  return sentryId != null;
-}
\ No newline at end of file
diff --git a/lib/inventree/stock.dart b/lib/inventree/stock.dart
index ff8189cd..827553b6 100644
--- a/lib/inventree/stock.dart
+++ b/lib/inventree/stock.dart
@@ -138,14 +138,13 @@ class InvenTreeStockItem extends InvenTreeModel {
     // TODO
   }
 
-  List<InvenTreePartTestTemplate> testTemplates = List<InvenTreePartTestTemplate>();
+  List<InvenTreePartTestTemplate> testTemplates = [];
 
   int get testTemplateCount => testTemplates.length;
 
   // Get all the test templates associated with this StockItem
-  Future<void> getTestTemplates(BuildContext context, {bool showDialog=false}) async {
+  Future<void> getTestTemplates({bool showDialog=false}) async {
     await InvenTreePartTestTemplate().list(
-      context,
       filters: {
         "part": "${partId}",
       },
@@ -160,14 +159,13 @@ class InvenTreeStockItem extends InvenTreeModel {
     });
   }
 
-  List<InvenTreeStockItemTestResult> testResults = List<InvenTreeStockItemTestResult>();
+  List<InvenTreeStockItemTestResult> testResults = [];
 
   int get testResultCount => testResults.length;
 
-  Future<void> getTestResults(BuildContext context) async {
+  Future<void> getTestResults() async {
 
     await InvenTreeStockItemTestResult().list(
-      context,
       filters: {
         "stock_item": "${pk}",
         "user_detail": "true",
@@ -183,7 +181,7 @@ class InvenTreeStockItem extends InvenTreeModel {
     });
   }
 
-  Future<bool> uploadTestResult(BuildContext context, String testName, bool result, {String value, String notes, File attachment}) async {
+  Future<bool> uploadTestResult(BuildContext context, String testName, bool result, {String? value, String? notes, File? attachment}) async {
 
     Map<String, String> data = {
       "stock_item": pk.toString(),
@@ -204,7 +202,7 @@ class InvenTreeStockItem extends InvenTreeModel {
      * TODO: Is there a nice way to refactor this one?
      */
     if (attachment == null) {
-      var _result = await InvenTreeStockItemTestResult().create(context, data);
+      var _result = await InvenTreeStockItemTestResult().create(data);
 
       return (_result != null) && (_result is InvenTreeStockItemTestResult);
     } else {
@@ -224,12 +222,12 @@ class InvenTreeStockItem extends InvenTreeModel {
 
   int get partId => jsondata['part'] ?? -1;
 
-  int get trackingItemCount => jsondata['tracking_items'] as int ?? 0;
+  int get trackingItemCount => (jsondata['tracking_items'] ?? 0) as int;
 
   // Date of last update
   String get updated => jsondata["updated"] ?? "";
 
-  DateTime get stocktakeDate {
+  DateTime? get stocktakeDate {
     if (jsondata.containsKey("stocktake_date")) {
       if (jsondata["stocktake_date"] == null) {
         return null;
@@ -292,15 +290,18 @@ class InvenTreeStockItem extends InvenTreeModel {
    */
   String get partThumbnail {
 
-    String thumb;
+    String thumb = "";
 
-    if (jsondata.containsKey('part_detail')) {
-      thumb = jsondata['part_detail']['thumbnail'] as String ?? '';
+    thumb = jsondata['part_detail']?['thumbnail'] ?? '';
+
+    // Use 'image' as a backup
+    if (thumb.isEmpty) {
+      thumb = jsondata['part_detail']?['image'] ?? '';
     }
 
     // Try a different approach
     if (thumb.isEmpty) {
-      jsondata['part__thumbnail'] as String ?? '';
+      thumb = jsondata['part__thumbnail'] ?? '';
     }
 
     // Still no thumbnail? Use the 'no image' image
@@ -309,7 +310,7 @@ class InvenTreeStockItem extends InvenTreeModel {
     return thumb;
   }
 
-  int get supplierPartId => jsondata['supplier_part'] as int ?? -1;
+  int get supplierPartId => (jsondata['supplier_part'] ?? -1) as int;
 
   String get supplierImage {
     String thumb = '';
@@ -341,9 +342,9 @@ class InvenTreeStockItem extends InvenTreeModel {
     return sku;
   }
 
-  String get serialNumber => jsondata['serial'] as String ?? null;
+  String get serialNumber => jsondata['serial'] ?? "";
 
-  double get quantity => double.tryParse(jsondata['quantity'].toString() ?? '0');
+  double get quantity => double.tryParse(jsondata['quantity'].toString()) ?? 0;
 
   String get quantityString {
 
@@ -354,9 +355,9 @@ class InvenTreeStockItem extends InvenTreeModel {
     }
   }
 
-  int get locationId => jsondata['location'] as int ?? -1;
+  int get locationId => (jsondata['location'] ?? -1) as int;
 
-  bool isSerialized() => serialNumber != null && quantity.toInt() == 1;
+  bool isSerialized() => serialNumber.isNotEmpty && quantity.toInt() == 1;
 
   String serialOrQuantityDisplay() {
     if (isSerialized()) {
@@ -397,10 +398,10 @@ class InvenTreeStockItem extends InvenTreeModel {
   String get displayQuantity {
     // Display either quantity or serial number!
 
-    if (serialNumber != null) {
+    if (serialNumber.isNotEmpty) {
       return "SN: $serialNumber";
     } else {
-      return quantity.toString().trim();
+      return quantityString;
     }
   }
 
@@ -420,7 +421,7 @@ class InvenTreeStockItem extends InvenTreeModel {
    * - Remove
    * - Count
    */
-  Future<bool> adjustStock(BuildContext context, String endpoint, double q, {String notes}) async {
+  Future<bool> adjustStock(BuildContext context, String endpoint, double q, {String? notes}) async {
 
     // Serialized stock cannot be adjusted
     if (isSerialized()) {
@@ -456,30 +457,29 @@ class InvenTreeStockItem extends InvenTreeModel {
     return true;
   }
 
-  Future<bool> countStock(BuildContext context, double q, {String notes}) async {
+  Future<bool> countStock(BuildContext context, double q, {String? notes}) async {
 
-    final bool result = await adjustStock(context, "/stock/count", q, notes: notes);
+    final bool result = await adjustStock(context, "/stock/count/", q, notes: notes);
 
     return result;
   }
 
-  Future<bool> addStock(BuildContext context, double q, {String notes}) async {
+  Future<bool> addStock(BuildContext context, double q, {String? notes}) async {
 
     final bool result = await adjustStock(context,  "/stock/add/", q, notes: notes);
 
     return result;
   }
 
-  Future<bool> removeStock(BuildContext context, double q, {String notes}) async {
+  Future<bool> removeStock(BuildContext context, double q, {String? notes}) async {
 
     final bool result = await adjustStock(context, "/stock/remove/", q, notes: notes);
 
     return result;
   }
 
-  Future<bool> transferStock(int location, {double quantity, String notes}) async {
-    if (quantity == null) {} else
-    if ((quantity < 0) || (quantity > this.quantity)) {
+  Future<bool> transferStock(int location, {double? quantity, String? notes}) async {
+    if ((quantity == null) || (quantity < 0) || (quantity > this.quantity)) {
       quantity = this.quantity;
     }
 
diff --git a/lib/l10.dart b/lib/l10.dart
index 5225a547..04b70f40 100644
--- a/lib/l10.dart
+++ b/lib/l10.dart
@@ -1,9 +1,22 @@
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
-import 'package:one_context/one_context.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations_en.dart';
 
+import 'package:one_context/one_context.dart';
+import 'package:flutter/material.dart';
 
 // Shortcut function to reduce boilerplate!
 I18N L10()
 {
-  return I18N.of(OneContext().context);
+  BuildContext? _ctx = OneContext().context;
+
+  if (_ctx != null) {
+    I18N? i18n = I18N.of(_ctx);
+
+    if (i18n != null) {
+      return i18n;
+    }
+  }
+
+  // Fallback for "null" context
+   return I18NEn();
 }
\ No newline at end of file
diff --git a/lib/l10n b/lib/l10n
index 05a5cbf6..9cc07cdb 160000
--- a/lib/l10n
+++ b/lib/l10n
@@ -1 +1 @@
-Subproject commit 05a5cbf63b4b5479162905def9fdadf21041212e
+Subproject commit 9cc07cdb0ec0012abcec827fc776d7c5473bb75e
diff --git a/lib/main.dart b/lib/main.dart
index 3d8fbb56..a84abe83 100644
--- a/lib/main.dart
+++ b/lib/main.dart
@@ -52,7 +52,7 @@ class InvenTreeApp extends StatelessWidget {
     return MaterialApp(
       builder: OneContext().builder,
       navigatorKey: OneContext().key,
-      onGenerateTitle: (BuildContext context) => I18N.of(context).appTitle,
+      onGenerateTitle: (BuildContext context) => I18N.of(context)!.appTitle,
       theme: ThemeData(
         primarySwatch: Colors.lightBlue,
         secondaryHeaderColor: Colors.blueGrey,
diff --git a/lib/preferences.dart b/lib/preferences.dart
index 3be8e8c7..27a416f0 100644
--- a/lib/preferences.dart
+++ b/lib/preferences.dart
@@ -15,15 +15,19 @@ class InvenTreePreferencesDB {
 
   InvenTreePreferencesDB._();
 
-  Completer<Database> _dbOpenCompleter;
+  Completer<Database> _dbOpenCompleter = Completer();
+
+  bool isOpen = false;
 
   Future<Database> get database async {
-    // If completer is null, AppDatabaseClass is newly instantiated, so database is not yet opened
-    if (_dbOpenCompleter == null) {
-      _dbOpenCompleter = Completer();
+
+    if (!isOpen) {
       // Calling _openDatabase will also complete the completer with database instance
       _openDatabase();
+
+      isOpen = true;
     }
+
     // If the database is already opened, awaiting the future will happen instantly.
     // Otherwise, awaiting the returned future will take some time - until complete() is called
     // on the Completer in _openDatabase() below.
diff --git a/lib/settings/login.dart b/lib/settings/login.dart
index 13105250..8dbaf324 100644
--- a/lib/settings/login.dart
+++ b/lib/settings/login.dart
@@ -26,7 +26,7 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
 
   final GlobalKey<FormState> _addProfileKey = new GlobalKey<FormState>();
 
-  List<UserProfile> profiles;
+  List<UserProfile> profiles = [];
 
   _InvenTreeLoginSettingsState() {
     _reload();
@@ -40,14 +40,14 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
     });
   }
 
-  void _editProfile(BuildContext context, {UserProfile userProfile, bool createNew = false}) {
+  void _editProfile(BuildContext context, {UserProfile? userProfile, bool createNew = false}) {
 
     var _name;
     var _server;
     var _username;
     var _password;
 
-    UserProfile profile;
+    UserProfile? profile;
 
     if (userProfile != null) {
       profile = userProfile;
@@ -69,10 +69,10 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
             _addProfile(profile);
           } else {
 
-            profile.name = _name;
-            profile.server = _server;
-            profile.username = _username;
-            profile.password = _password;
+            profile?.name = _name;
+            profile?.server = _server;
+            profile?.username = _username;
+            profile?.password = _password;
 
             _updateProfile(profile);
 
@@ -82,28 +82,28 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
         StringField(
           label: L10().name,
           hint: "Enter profile name",
-          initial: createNew ? '' : profile.name,
+          initial: createNew ? '' : profile?.name ?? '',
           onSaved: (value) => _name = value,
           validator: _validateProfileName,
         ),
         StringField(
           label: L10().server,
           hint: "http[s]://<server>:<port>",
-          initial: createNew ? '' : profile.server,
+          initial: createNew ? '' : profile?.server ?? '',
           validator: _validateServer,
           onSaved: (value) => _server = value,
         ),
         StringField(
           label: L10().username,
           hint: L10().enterPassword,
-          initial: createNew ? '' : profile.username,
+          initial: createNew ? '' : profile?.username ?? '',
           onSaved: (value) => _username = value,
           validator: _validateUsername,
         ),
         StringField(
           label: L10().password,
           hint: L10().enterUsername,
-          initial: createNew ? '' : profile.password,
+          initial: createNew ? '' : profile?.password ?? '',
           onSaved: (value) => _password = value,
           validator: _validatePassword,
         )
@@ -111,7 +111,7 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
     );
   }
 
-  String _validateProfileName(String value) {
+  String? _validateProfileName(String value) {
 
     if (value.isEmpty) {
       return 'Profile name cannot be empty';
@@ -122,14 +122,14 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
     return null;
   }
 
-  String _validateServer(String value) {
+  String? _validateServer(String value) {
 
     if (value.isEmpty) {
-      return 'Server cannot be empty';
+      return L10().serverEmpty;
     }
 
     if (!value.startsWith("http:") && !value.startsWith("https:")) {
-      return 'Server must start with http[s]';
+      return L10().serverStart;
     }
 
     // TODO: URL validator
@@ -137,17 +137,17 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
     return null;
   }
 
-  String _validateUsername(String value) {
+  String? _validateUsername(String value) {
     if (value.isEmpty) {
-      return 'Username cannot be empty';
+      return L10().usernameEmpty;
     }
 
     return null;
   }
 
-  String _validatePassword(String value) {
+  String? _validatePassword(String value) {
     if (value.isEmpty) {
-      return 'Password cannot be empty';
+      return L10().passwordEmpty;
     }
 
     return null;
@@ -158,12 +158,18 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
     // Disconnect InvenTree
     InvenTreeAPI().disconnectFromServer();
 
-    await UserProfileDBManager().selectProfile(profile.key);
+    var key = profile.key;
+
+    if (key == null) {
+      return;
+    }
+
+    await UserProfileDBManager().selectProfile(key);
 
     _reload();
 
     // Attempt server login (this will load the newly selected profile
-    InvenTreeAPI().connectToServer(_loginKey.currentContext).then((result) {
+    InvenTreeAPI().connectToServer().then((result) {
       _reload();
     });
 
@@ -176,21 +182,25 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
 
     _reload();
 
-    if (InvenTreeAPI().isConnected() && profile.key == InvenTreeAPI().profile.key) {
+    if (InvenTreeAPI().isConnected() && profile.key == (InvenTreeAPI().profile?.key ?? '')) {
       InvenTreeAPI().disconnectFromServer();
     }
   }
 
-  void _updateProfile(UserProfile profile) async {
+  void _updateProfile(UserProfile? profile) async {
+
+    if (profile == null) {
+      return;
+    }
 
     await UserProfileDBManager().updateProfile(profile);
 
     _reload();
 
-    if (InvenTreeAPI().isConnected() && profile.key == InvenTreeAPI().profile.key) {
+    if (InvenTreeAPI().isConnected() && InvenTreeAPI().profile != null && profile.key == (InvenTreeAPI().profile?.key ?? '')) {
       // Attempt server login (this will load the newly selected profile
 
-      InvenTreeAPI().connectToServer(_loginKey.currentContext).then((result) {
+      InvenTreeAPI().connectToServer().then((result) {
         _reload();
       });
     }
@@ -203,13 +213,13 @@ class _InvenTreeLoginSettingsState extends State<InvenTreeLoginSettingsWidget> {
     _reload();
   }
 
-  Widget _getProfileIcon(UserProfile profile) {
+  Widget? _getProfileIcon(UserProfile profile) {
 
     // Not selected? No icon for you!
-    if (profile == null || !profile.selected) return null;
+    if (!profile.selected) return null;
 
     // Selected, but (for some reason) not the same as the API...
-    if (InvenTreeAPI().profile == null || InvenTreeAPI().profile.key != profile.key) {
+    if ((InvenTreeAPI().profile?.key ?? '') != profile.key) {
       return FaIcon(
         FontAwesomeIcons.questionCircle,
         color: Color.fromRGBO(250, 150, 50, 1)
diff --git a/lib/user_profile.dart b/lib/user_profile.dart
index cef17f31..efbd81ca 100644
--- a/lib/user_profile.dart
+++ b/lib/user_profile.dart
@@ -9,32 +9,32 @@ class UserProfile {
 
   UserProfile({
     this.key,
-    this.name,
-    this.server,
-    this.username,
-    this.password,
-    this.selected,
+    this.name = "",
+    this.server = "",
+    this.username = "",
+    this.password = "",
+    this.selected = false,
   });
 
   // ID of the profile
-  int key;
+  int? key;
 
   // Name of the user profile
-  String name;
+  String name = "";
 
   // Base address of the InvenTree server
-  String server;
+  String server = "";
 
   // Username
-  String username;
+  String username = "";
 
   // Password
-  String password;
+  String password = "";
 
   bool selected = false;
 
   // User ID (will be provided by the server on log-in)
-  int user_id;
+  int user_id = -1;
 
   factory UserProfile.fromJson(int key, Map<String, dynamic> json, bool isSelected) => UserProfile(
     key: key,
@@ -122,7 +122,7 @@ class UserProfileDBManager {
     print("Deleted user profile <${profile.key}> - '${profile.name}'");
   }
 
-  Future<UserProfile> getSelectedProfile() async {
+  Future<UserProfile?> getSelectedProfile() async {
     /*
      * Return the currently selected profile.
      *
@@ -133,7 +133,7 @@ class UserProfileDBManager {
 
     final profiles = await store.find(await _db);
 
-    List<UserProfile> profileList = new List<UserProfile>();
+    List<UserProfile> profileList = [];
 
     for (int idx = 0; idx < profiles.length; idx++) {
 
@@ -158,7 +158,7 @@ class UserProfileDBManager {
 
     final profiles = await store.find(await _db);
 
-    List<UserProfile> profileList = new List<UserProfile>();
+    List<UserProfile> profileList = [];
 
     for (int idx = 0; idx < profiles.length; idx++) {
 
diff --git a/lib/widget/category_display.dart b/lib/widget/category_display.dart
index 4725cc30..3f4533d3 100644
--- a/lib/widget/category_display.dart
+++ b/lib/widget/category_display.dart
@@ -2,6 +2,7 @@
 import 'package:InvenTree/api.dart';
 import 'package:InvenTree/app_settings.dart';
 import 'package:InvenTree/inventree/part.dart';
+import 'package:InvenTree/inventree/sentry.dart';
 import 'package:InvenTree/widget/progress.dart';
 
 import 'package:InvenTree/l10.dart';
@@ -23,9 +24,9 @@ import 'package:infinite_scroll_pagination/infinite_scroll_pagination.dart';
 
 class CategoryDisplayWidget extends StatefulWidget {
 
-  CategoryDisplayWidget(this.category, {Key key}) : super(key: key);
+  CategoryDisplayWidget(this.category, {Key? key}) : super(key: key);
 
-  final InvenTreePartCategory category;
+  final InvenTreePartCategory? category;
 
   @override
   _CategoryDisplayState createState() => _CategoryDisplayState(category);
@@ -81,7 +82,7 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
 
   void _editCategory(Map<String, String> values) async {
 
-    final bool result = await category.update(context, values: values);
+    final bool result = await category!.update(values: values);
 
     showSnackIcon(
       result ? "Category edited" : "Category editing failed",
@@ -93,6 +94,11 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
 
   void _editCategoryDialog() {
 
+    // Cannot edit top-level category
+    if (category == null) {
+      return;
+    }
+
     var _name;
     var _description;
 
@@ -108,12 +114,12 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
       fields: <Widget>[
         StringField(
           label: L10().name,
-          initial: category.name,
+          initial: category?.name,
           onSaved: (value) => _name = value
         ),
         StringField(
           label: L10().description,
-          initial: category.description,
+          initial: category?.description,
           onSaved: (value) => _description = value
         )
       ]
@@ -123,9 +129,9 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
   _CategoryDisplayState(this.category) {}
 
   // The local InvenTreePartCategory object
-  final InvenTreePartCategory category;
+  final InvenTreePartCategory? category;
 
-  List<InvenTreePartCategory> _subcategories = List<InvenTreePartCategory>();
+  List<InvenTreePartCategory> _subcategories = [];
 
   @override
   Future<void> onBuild(BuildContext context) async {
@@ -133,17 +139,17 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
   }
 
   @override
-  Future<void> request(BuildContext context) async {
+  Future<void> request() async {
 
     int pk = category?.pk ?? -1;
 
     // Update the category
     if (category != null) {
-      await category.reload(context);
+      await category!.reload();
     }
 
     // Request a list of sub-categories under this one
-    await InvenTreePartCategory().list(context, filters: {"parent": "$pk"}).then((var cats) {
+    await InvenTreePartCategory().list(filters: {"parent": "$pk"}).then((var cats) {
       _subcategories.clear();
 
       for (var cat in cats) {
@@ -168,10 +174,10 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
 
       List<Widget> children = [
         ListTile(
-          title: Text("${category.name}",
+          title: Text("${category?.name}",
               style: TextStyle(fontWeight: FontWeight.bold)
           ),
-          subtitle: Text("${category.description}"),
+          subtitle: Text("${category?.description}"),
         ),
       ];
 
@@ -179,14 +185,14 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
         children.add(
             ListTile(
               title: Text(L10().parentCategory),
-              subtitle: Text("${category.parentpathstring}"),
+              subtitle: Text("${category?.parentpathstring}"),
               leading: FaIcon(FontAwesomeIcons.levelUpAlt),
               onTap: () {
-                if (category.parentId < 0) {
+                if (category == null || ((category?.parentId ?? 0) < 0)) {
                   Navigator.push(context, MaterialPageRoute(builder: (context) => CategoryDisplayWidget(null)));
                 } else {
                   // TODO - Refactor this code into the InvenTreePart class
-                  InvenTreePartCategory().get(context, category.parentId).then((var cat) {
+                  InvenTreePartCategory().get(category?.parentId ?? -1).then((var cat) {
                     if (cat is InvenTreePartCategory) {
                       Navigator.push(context, MaterialPageRoute(builder: (context) => CategoryDisplayWidget(cat)));
                     }
@@ -290,6 +296,8 @@ class _CategoryDisplayState extends RefreshableState<CategoryDisplayWidget> {
         return ListView(
           children: actionTiles()
         );
+      default:
+        return ListView();
     }
   }
 }
@@ -306,7 +314,7 @@ class SubcategoryList extends StatelessWidget {
   void _openCategory(BuildContext context, int pk) {
 
     // Attempt to load the sub-category.
-    InvenTreePartCategory().get(context, pk).then((var cat) {
+    InvenTreePartCategory().get(pk).then((var cat) {
       if (cat is InvenTreePartCategory) {
 
         Navigator.push(context, MaterialPageRoute(builder: (context) => CategoryDisplayWidget(cat)));
@@ -348,7 +356,7 @@ class PaginatedPartList extends StatefulWidget {
 
   final Map<String, String> filters;
 
-  Function onTotalChanged;
+  Function(int)? onTotalChanged;
 
   PaginatedPartList(this.filters, {this.onTotalChanged});
 
@@ -363,7 +371,7 @@ class _PaginatedPartListState extends State<PaginatedPartList> {
 
   String _searchTerm = "";
 
-  Function onTotalChanged;
+  Function(int)? onTotalChanged;
 
   final Map<String, String> filters;
 
@@ -393,21 +401,21 @@ class _PaginatedPartListState extends State<PaginatedPartList> {
 
       Map<String, String> params = filters;
 
-      params["search"] = _searchTerm ?? "";
+      params["search"] = _searchTerm;
 
       final bool cascade = await InvenTreeSettingsManager().getValue("partSubcategory", false);
       params["cascade"] = "${cascade}";
 
       final page = await InvenTreePart().listPaginated(_pageSize, pageKey, filters: params);
-      int pageLength = page.length ?? 0;
-      int pageCount = page.count ?? 0;
+      int pageLength = page?.length ?? 0;
+      int pageCount = page?.count ?? 0;
 
       final isLastPage = pageLength < _pageSize;
 
       // Construct a list of part objects
       List<InvenTreePart> parts = [];
 
-      if (page == null) {
+      if (page != null) {
         for (var result in page.results) {
           if (result is InvenTreePart) {
             parts.add(result);
@@ -423,22 +431,24 @@ class _PaginatedPartListState extends State<PaginatedPartList> {
       }
 
       if (onTotalChanged != null) {
-        onTotalChanged(pageCount);
+        onTotalChanged!(pageCount);
       }
 
       setState(() {
         resultCount = pageCount;
       });
 
-    } catch (error) {
+    } catch (error, stackTrace) {
       print("Error! - ${error.toString()}");
       _pagingController.error = error;
+
+      sentryReportError(error, stackTrace);
     }
   }
 
   void _openPart(BuildContext context, int pk) {
     // Attempt to load the part information
-    InvenTreePart().get(context, pk).then((var part) {
+    InvenTreePart().get(pk).then((var part) {
       if (part is InvenTreePart) {
 
         Navigator.push(context, MaterialPageRoute(builder: (context) => PartDetailWidget(part)));
diff --git a/lib/widget/company_detail.dart b/lib/widget/company_detail.dart
index 5aec037c..04134783 100644
--- a/lib/widget/company_detail.dart
+++ b/lib/widget/company_detail.dart
@@ -13,7 +13,7 @@ class CompanyDetailWidget extends StatefulWidget {
 
   final InvenTreeCompany company;
 
-  CompanyDetailWidget(this.company, {Key key}) : super(key: key);
+  CompanyDetailWidget(this.company, {Key? key}) : super(key: key);
 
   @override
   _CompanyDetailState createState() => _CompanyDetailState(company);
@@ -31,8 +31,8 @@ class _CompanyDetailState extends RefreshableState<CompanyDetailWidget> {
   String getAppBarTitle(BuildContext context) => L10().company;
 
   @override
-  Future<void> request(BuildContext context) async {
-    await company.reload(context);
+  Future<void> request() async {
+    await company.reload();
   }
 
   _CompanyDetailState(this.company) {
@@ -42,7 +42,7 @@ class _CompanyDetailState extends RefreshableState<CompanyDetailWidget> {
   void _saveCompany(Map<String, String> values) async {
     Navigator.of(context).pop();
 
-    var response = await company.update(context, values: values);
+    var response = await company.update(values: values);
 
     refresh();
   }
@@ -66,8 +66,8 @@ class _CompanyDetailState extends RefreshableState<CompanyDetailWidget> {
           FlatButton(
             child: Text(L10().save),
             onPressed: () {
-              if (_editCompanyKey.currentState.validate()) {
-                _editCompanyKey.currentState.save();
+              if (_editCompanyKey.currentState!.validate()) {
+                _editCompanyKey.currentState!.save();
 
                 _saveCompany({
                   "name": _name,
@@ -107,7 +107,7 @@ class _CompanyDetailState extends RefreshableState<CompanyDetailWidget> {
 
   List<Widget> _companyTiles() {
 
-    var tiles = List<Widget>();
+    List<Widget> tiles = [];
 
     bool sep = false;
 
diff --git a/lib/widget/company_list.dart b/lib/widget/company_list.dart
index deada540..56fc76af 100644
--- a/lib/widget/company_list.dart
+++ b/lib/widget/company_list.dart
@@ -11,8 +11,8 @@ import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 
 abstract class CompanyListWidget extends StatefulWidget {
 
-  String title;
-  Map<String, String> filters;
+  String title = "";
+  Map<String, String> filters = {};
 
   @override
   _CompanyListState createState() => _CompanyListState(title, filters);
@@ -39,9 +39,9 @@ class CustomerListWidget extends CompanyListWidget {
 
 class _CompanyListState extends RefreshableState<CompanyListWidget> {
 
-  var _companies = new List<InvenTreeCompany>();
+  List<InvenTreeCompany> _companies = [];
 
-  var _filteredCompanies = new List<InvenTreeCompany>();
+  List<InvenTreeCompany> _filteredCompanies = [];
 
   String _title = "Companies";
 
@@ -58,9 +58,9 @@ class _CompanyListState extends RefreshableState<CompanyListWidget> {
   }
 
   @override
-  Future<void> request(BuildContext context) async {
+  Future<void> request() async {
 
-    await InvenTreeCompany().list(context, filters: _filters).then((var companies) {
+    await InvenTreeCompany().list(filters: _filters).then((var companies) {
 
       _companies.clear();
 
@@ -96,8 +96,10 @@ class _CompanyListState extends RefreshableState<CompanyListWidget> {
         leading: InvenTreeAPI().getImage(company.image),
         onTap: () {
           if (company.pk > 0) {
-            InvenTreeCompany().get(context, company.pk).then((var c) {
-              Navigator.push(context, MaterialPageRoute(builder: (context) => CompanyDetailWidget(c)));
+            InvenTreeCompany().get(company.pk).then((var c) {
+              if (c != null && c is InvenTreeCompany) {
+                Navigator.push(context, MaterialPageRoute(builder: (context) => CompanyDetailWidget(c)));
+              }
             });
           }
         },
diff --git a/lib/widget/dialogs.dart b/lib/widget/dialogs.dart
index 6d636fc0..8cf13f6d 100644
--- a/lib/widget/dialogs.dart
+++ b/lib/widget/dialogs.dart
@@ -8,15 +8,10 @@ import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 import 'package:InvenTree/l10.dart';
 import 'package:one_context/one_context.dart';
 
-Future<void> confirmationDialog(String title, String text, {String acceptText, String rejectText, Function onAccept, Function onReject}) async {
+Future<void> confirmationDialog(String title, String text, {String? acceptText, String? rejectText, Function? onAccept, Function? onReject}) async {
 
-  if (acceptText == null || acceptText.isEmpty) {
-    acceptText = L10().ok;
-  }
-
-  if (rejectText == null || rejectText.isEmpty) {
-    rejectText = L10().cancel;
-  }
+  String _accept = acceptText ?? L10().ok;
+  String _reject = rejectText ?? L10().cancel;
 
   OneContext().showDialog(
     builder: (BuildContext context) {
@@ -28,7 +23,7 @@ Future<void> confirmationDialog(String title, String text, {String acceptText, S
         content: Text(text),
         actions: [
           FlatButton(
-            child: Text(rejectText),
+            child: Text(_reject),
             onPressed: () {
               // Close this dialog
               Navigator.pop(context);
@@ -39,7 +34,7 @@ Future<void> confirmationDialog(String title, String text, {String acceptText, S
             }
           ),
           FlatButton(
-            child: Text(acceptText),
+            child: Text(_accept),
             onPressed: () {
               // Close this dialog
               Navigator.pop(context);
@@ -56,17 +51,14 @@ Future<void> confirmationDialog(String title, String text, {String acceptText, S
 }
 
 
-Future<void> showInfoDialog(BuildContext context, String title, String description, {IconData icon = FontAwesomeIcons.info, String info, Function onDismissed}) async {
+Future<void> showInfoDialog(String title, String description, {IconData icon = FontAwesomeIcons.info, String? info, Function()? onDismissed}) async {
 
-  if (info == null || info.isEmpty) {
-    info = L10().info;
-  }
+  String _info = info ?? L10().info;
 
-  showDialog(
-    context: context,
+  OneContext().showDialog(
     builder: (BuildContext context) => SimpleDialog(
       title: ListTile(
-        title: Text(info),
+        title: Text(_info),
         leading: FaIcon(icon),
       ),
       children: <Widget>[
@@ -83,16 +75,14 @@ Future<void> showInfoDialog(BuildContext context, String title, String descripti
   });
 }
 
-Future<void> showErrorDialog(String title, String description, {IconData icon = FontAwesomeIcons.exclamationCircle, String error, Function onDismissed}) async {
+Future<void> showErrorDialog(String title, String description, {IconData icon = FontAwesomeIcons.exclamationCircle, String? error, Function? onDismissed}) async {
 
-  if (error == null || error.isEmpty) {
-    error = L10().error;
-  }
+  String _error = error ?? L10().error;
 
   OneContext().showDialog(
     builder: (context) => SimpleDialog(
       title: ListTile(
-        title: Text(error),
+        title: Text(_error),
         leading: FaIcon(icon),
       ),
       children: [
@@ -111,7 +101,7 @@ Future<void> showErrorDialog(String title, String description, {IconData icon =
 
 Future<void> showServerError(String title, String description) async {
 
-  if (title == null || title.isEmpty) {
+  if (title.isEmpty) {
     title = L10().serverError;
   }
 
@@ -140,8 +130,6 @@ Future<void> showServerError(String title, String description) async {
 
 Future<void> showStatusCodeError(int status, {int expected = 200}) async {
 
-  BuildContext ctx = OneContext().context;
-
   String msg = L10().responseInvalid;
   String extra = "Server responded with status code ${status}";
 
@@ -174,7 +162,7 @@ Future<void> showStatusCodeError(int status, {int expected = 200}) async {
   );
 }
 
-Future<void> showTimeoutError(BuildContext context) async {
+Future<void> showTimeoutError() async {
 
   // Use OneContext as "sometimes" context is null here?
   var ctx = OneContext().context;
@@ -182,42 +170,49 @@ Future<void> showTimeoutError(BuildContext context) async {
   await showServerError(L10().timeout, L10().noResponse);
 }
 
-void showFormDialog(String title, {String acceptText, String cancelText, GlobalKey<FormState> key, List<Widget> fields, List<Widget> actions, Function callback}) {
+void showFormDialog(String title, {String? acceptText, String? cancelText, GlobalKey<FormState>? key, List<Widget>? fields, List<Widget>? actions, Function? callback}) {
 
-  BuildContext dialogContext;
+  BuildContext? dialogContext;
 
   var ctx = OneContext().context;
 
-  if (acceptText == null) {
-    acceptText = L10().save;
-  }
-
-  if (cancelText == null) {
-    cancelText = L10().cancel;
-  }
+  String _accept = acceptText ?? L10().save;
+  String _cancel = cancelText ?? L10().cancel;
 
   // Undefined actions = OK + Cancel
   if (actions == null) {
     actions = <Widget>[
       FlatButton(
-        child: Text(cancelText),
+        child: Text(_cancel),
         onPressed: () {
           // Close the form
-          Navigator.pop(dialogContext);
+          var _ctx = dialogContext;
+          if (_ctx != null) {
+            Navigator.pop(_ctx);
+          }
         }
       ),
       FlatButton(
-        child: Text(acceptText),
+        child: Text(_accept),
         onPressed: () {
-          if (key.currentState.validate()) {
-            key.currentState.save();
 
-            // Close the dialog
-            Navigator.pop(dialogContext);
+          var _key = key;
 
-            // Callback
-            if (callback != null) {
-              callback();
+          if (_key != null && _key.currentState != null) {
+            if (_key.currentState!.validate()) {
+              _key.currentState!.save();
+
+              // Close the dialog
+              var _ctx = dialogContext;
+
+              if (_ctx != null) {
+                Navigator.pop(_ctx);
+              }
+
+              // Callback
+              if (callback != null) {
+                callback();
+              }
             }
           }
         }
@@ -225,6 +220,8 @@ void showFormDialog(String title, {String acceptText, String cancelText, GlobalK
     ];
   }
 
+  List<Widget> _fields = fields ?? [];
+
   OneContext().showDialog(
     builder: (BuildContext context) {
       dialogContext = context;
@@ -238,7 +235,7 @@ void showFormDialog(String title, {String acceptText, String cancelText, GlobalK
                       mainAxisSize: MainAxisSize.min,
                       mainAxisAlignment: MainAxisAlignment.start,
                       crossAxisAlignment: CrossAxisAlignment.start,
-                      children: fields
+                      children: _fields
                   )
               )
           )
diff --git a/lib/widget/fields.dart b/lib/widget/fields.dart
index 7039f128..0572f2b6 100644
--- a/lib/widget/fields.dart
+++ b/lib/widget/fields.dart
@@ -52,10 +52,10 @@ class ImagePickerField extends FormField<File> {
 
   }
 
-  ImagePickerField(BuildContext context, {String label = "Attach Image", Function onSaved, bool required = false}) :
+  ImagePickerField(BuildContext context, {String? label, Function(File?)? onSaved, bool required = false}) :
       super(
         onSaved: onSaved,
-        validator: (File img) {
+        validator: (File? img) {
           if (required && (img == null)) {
             return L10().required;
           }
@@ -63,10 +63,13 @@ class ImagePickerField extends FormField<File> {
           return null;
         },
         builder: (FormFieldState<File> state) {
+
+          String _label = label ?? L10().attachImage;
+
           return InputDecorator(
             decoration: InputDecoration(
               errorText: state.errorText,
-              labelText: required ? label + "*" : label,
+              labelText: required ? _label + "*" : _label,
             ),
             child: Row(
               mainAxisAlignment: MainAxisAlignment.spaceEvenly,
@@ -92,7 +95,7 @@ class ImagePickerField extends FormField<File> {
 
 
 class CheckBoxField extends FormField<bool> {
-  CheckBoxField({String label, String hint, bool initial = false, Function onSaved}) :
+  CheckBoxField({String? label, String? hint, bool initial = false, Function(bool?)? onSaved}) :
       super(
         onSaved: onSaved,
         initialValue: initial,
@@ -111,7 +114,7 @@ class CheckBoxField extends FormField<bool> {
 
 class StringField extends TextFormField {
 
-  StringField({String label, String hint, String initial, Function onSaved, Function validator, bool allowEmpty = false, bool isEnabled = true}) :
+  StringField({String label = "", String? hint, String? initial, Function(String?)? onSaved, Function? validator, bool allowEmpty = false, bool isEnabled = true}) :
       super(
         decoration: InputDecoration(
           labelText: allowEmpty ? label : label + "*",
@@ -121,7 +124,7 @@ class StringField extends TextFormField {
         onSaved: onSaved,
         enabled: isEnabled,
         validator: (value) {
-          if (!allowEmpty && value.isEmpty) {
+          if (!allowEmpty && value != null && value.isEmpty) {
             return L10().valueCannotBeEmpty;
           }
 
@@ -140,7 +143,7 @@ class StringField extends TextFormField {
  */
 class QuantityField extends TextFormField {
 
-  QuantityField({String label = "", String hint = "", String initial = "", double max = null, TextEditingController controller}) :
+  QuantityField({String label = "", String hint = "", String initial = "", double? max, TextEditingController? controller}) :
       super(
         decoration: InputDecoration(
           labelText: label,
@@ -150,11 +153,10 @@ class QuantityField extends TextFormField {
         keyboardType: TextInputType.numberWithOptions(signed: false, decimal: true),
         validator: (value) {
 
-          if (value.isEmpty) return L10().quantityEmpty;
+          if (value != null && value.isEmpty) return L10().quantityEmpty;
 
-          double quantity = double.tryParse(value);
+          double quantity = double.tryParse(value.toString()) ?? 0;
 
-          if (quantity == null) return L10().quantityInvalid;
           if (quantity <= 0) return L10().quantityPositive;
           if ((max != null) && (quantity > max)) return "Quantity must not exceed ${max}";
 
diff --git a/lib/widget/home.dart b/lib/widget/home.dart
index 677522e3..f85c32bd 100644
--- a/lib/widget/home.dart
+++ b/lib/widget/home.dart
@@ -20,7 +20,7 @@ import 'package:InvenTree/widget/spinner.dart';
 import 'package:InvenTree/widget/drawer.dart';
 
 class InvenTreeHomePage extends StatefulWidget {
-  InvenTreeHomePage({Key key}) : super(key: key);
+  InvenTreeHomePage({Key? key}) : super(key: key);
 
   @override
   _InvenTreeHomePageState createState() => _InvenTreeHomePageState();
@@ -37,9 +37,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
   }
 
   // Selected user profile
-  UserProfile _profile;
-
-  BuildContext _context;
+  UserProfile? _profile;
 
   void _searchParts() {
     if (!InvenTreeAPI().checkConnection(context)) return;
@@ -113,7 +111,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
       if (!InvenTreeAPI().isConnected() && !InvenTreeAPI().isConnecting()) {
 
         // Attempt server connection
-        InvenTreeAPI().connectToServer(_homeKey.currentContext).then((result) {
+        InvenTreeAPI().connectToServer().then((result) {
           setState(() {});
         });
       }
@@ -171,7 +169,7 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
     } else {
       return ListTile(
         title: Text(L10().serverCouldNotConnect),
-        subtitle: Text("${_profile.server}"),
+        subtitle: Text("${_profile!.server}"),
         leading: FaIcon(FontAwesomeIcons.server),
         trailing: FaIcon(
           FontAwesomeIcons.timesCircle,
@@ -187,8 +185,6 @@ class _InvenTreeHomePageState extends State<InvenTreeHomePage> {
   @override
   Widget build(BuildContext context) {
 
-    _context = context;
-
     // This method is rerun every time setState is called, for instance as done
     // by the _incrementCounter method above.
     //
diff --git a/lib/widget/location_display.dart b/lib/widget/location_display.dart
index e6e75a12..8cc11536 100644
--- a/lib/widget/location_display.dart
+++ b/lib/widget/location_display.dart
@@ -1,6 +1,7 @@
 import 'package:InvenTree/api.dart';
 import 'package:InvenTree/app_settings.dart';
 import 'package:InvenTree/barcode.dart';
+import 'package:InvenTree/inventree/sentry.dart';
 import 'package:InvenTree/inventree/stock.dart';
 import 'package:InvenTree/widget/progress.dart';
 
@@ -20,11 +21,11 @@ import 'package:infinite_scroll_pagination/infinite_scroll_pagination.dart';
 
 class LocationDisplayWidget extends StatefulWidget {
 
-  LocationDisplayWidget(this.location, {Key key}) : super(key: key);
+  LocationDisplayWidget(this.location, {Key? key}) : super(key: key);
 
-  final InvenTreeStockLocation location;
+  final InvenTreeStockLocation? location;
 
-  final String title = "Location";
+  final String title = L10().stockLocation;
 
   @override
   _LocationDisplayState createState() => _LocationDisplayState(location);
@@ -32,12 +33,12 @@ class LocationDisplayWidget extends StatefulWidget {
 
 class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
 
-  final InvenTreeStockLocation location;
+  final InvenTreeStockLocation? location;
 
   final _editLocationKey = GlobalKey<FormState>();
 
   @override
-  String getAppBarTitle(BuildContext context) { return "Stock Location"; }
+  String getAppBarTitle(BuildContext context) { return L10().stockLocation; }
 
   @override
   List<Widget> getAppBarActions(BuildContext context) {
@@ -80,12 +81,16 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
 
   void _editLocation(Map<String, String> values) async {
 
-    final bool result = await location.update(context, values: values);
+    bool result = false;
 
-    showSnackIcon(
-      result ? "Location edited" : "Location editing failed",
-      success: result
-    );
+    if (location != null) {
+      result = await location!.update(values: values);
+
+      showSnackIcon(
+          result ? "Location edited" : "Location editing failed",
+          success: result
+      );
+    }
 
     refresh();
   }
@@ -95,6 +100,10 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
     var _name;
     var _description;
 
+    if (location == null) {
+      return;
+    }
+
     showFormDialog(L10().editLocation,
       key: _editLocationKey,
       callback: () {
@@ -106,12 +115,12 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
       fields: <Widget> [
         StringField(
           label: L10().name,
-          initial: location.name,
+          initial: location?.name ?? '',
           onSaved: (value) => _name = value,
         ),
         StringField(
           label: L10().description,
-          initial: location.description,
+          initial: location?.description ?? '',
           onSaved: (value) => _description = value,
         )
       ]
@@ -120,7 +129,7 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
 
   _LocationDisplayState(this.location) {}
 
-  List<InvenTreeStockLocation> _sublocations = List<InvenTreeStockLocation>();
+  List<InvenTreeStockLocation> _sublocations = [];
 
   String _locationFilter = '';
 
@@ -139,17 +148,17 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
   }
 
   @override
-  Future<void> request(BuildContext context) async {
+  Future<void> request() async {
 
     int pk = location?.pk ?? -1;
 
     // Reload location information
     if (location != null) {
-      await location.reload(context);
+      await location?.reload();
     }
 
     // Request a list of sub-locations under this one
-    await InvenTreeStockLocation().list(context, filters: {"parent": "$pk"}).then((var locs) {
+    await InvenTreeStockLocation().list(filters: {"parent": "$pk"}).then((var locs) {
       _sublocations.clear();
 
       for (var loc in locs) {
@@ -173,8 +182,9 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
 
       List<Widget> children = [
         ListTile(
-          title: Text("${location.name}"),
-          subtitle: Text("${location.description}"),
+          title: Text("${location!.name}"),
+          subtitle: Text("${location!.description}"),
+          trailing: Text("${location!.itemcount}"),
         ),
       ];
 
@@ -182,13 +192,17 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
         children.add(
             ListTile(
               title: Text(L10().parentCategory),
-              subtitle: Text("${location.parentpathstring}"),
+              subtitle: Text("${location!.parentpathstring}"),
               leading: FaIcon(FontAwesomeIcons.levelUpAlt),
               onTap: () {
-                if (location.parentId < 0) {
+
+                int parent = location?.parentId ?? -1;
+
+                if (parent < 0) {
                   Navigator.push(context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(null)));
                 } else {
-                  InvenTreeStockLocation().get(context, location.parentId).then((var loc) {
+
+                  InvenTreeStockLocation().get(parent).then((var loc) {
                     if (loc is InvenTreeStockLocation) {
                       Navigator.push(context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(loc)));
                     }
@@ -238,7 +252,7 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
     Map<String, String> filters = {};
 
     if (location != null) {
-      filters["location"] = "${location.pk}";
+      filters["location"] = "${location!.pk}";
     }
 
     switch (index) {
@@ -256,7 +270,7 @@ class _LocationDisplayState extends RefreshableState<LocationDisplayWidget> {
           ).toList()
         );
       default:
-        return null;
+        return ListView();
     }
   }
 
@@ -297,7 +311,7 @@ List<Widget> detailTiles() {
     List<Widget> tiles = [];
 
     tiles.add(locationDescriptionCard(includeActions: false));
-    
+
     if (location != null) {
       // Stock adjustment actions
       if (InvenTreeAPI().checkPermission('stock', 'change')) {
@@ -308,14 +322,19 @@ List<Widget> detailTiles() {
               leading: FaIcon(FontAwesomeIcons.exchangeAlt),
               trailing: FaIcon(FontAwesomeIcons.qrcode),
               onTap: () {
-                Navigator.push(
-                    context,
-                    MaterialPageRoute(builder: (context) =>
-                        InvenTreeQRView(
-                            StockLocationScanInItemsHandler(location)))
-                ).then((context) {
-                  refresh();
-                });
+
+                var _loc = location;
+
+                if (_loc != null) {
+                  Navigator.push(
+                      context,
+                      MaterialPageRoute(builder: (context) =>
+                          InvenTreeQRView(
+                              StockLocationScanInItemsHandler(_loc)))
+                  ).then((context) {
+                    refresh();
+                  });
+                }
               },
             )
         );
@@ -361,7 +380,7 @@ class SublocationList extends StatelessWidget {
 
   void _openLocation(BuildContext context, int pk) {
 
-    InvenTreeStockLocation().get(context, pk).then((var loc) {
+    InvenTreeStockLocation().get(pk).then((var loc) {
       if (loc is InvenTreeStockLocation) {
 
         Navigator.push(context, MaterialPageRoute(builder: (context) => LocationDisplayWidget(loc)));
@@ -452,35 +471,43 @@ class _PaginatedStockListState extends State<PaginatedStockList> {
       params["cascade"] = "${cascade}";
 
       final page = await InvenTreeStockItem().listPaginated(_pageSize, pageKey, filters: params);
-      final isLastPage = page.length < _pageSize;
+
+      int pageLength = page?.length ?? 0;
+      int pageCount = page?.count ?? 0;
+
+      final isLastPage = pageLength < _pageSize;
 
       // Construct a list of stock item objects
       List<InvenTreeStockItem> items = [];
 
-      for (var result in page.results) {
-        if (result is InvenTreeStockItem) {
-          items.add(result);
+      if (page != null) {
+        for (var result in page.results) {
+          if (result is InvenTreeStockItem) {
+            items.add(result);
+          }
         }
       }
 
       if (isLastPage) {
         _pagingController.appendLastPage(items);
       } else {
-        final int nextPageKey = pageKey + page.length;
+        final int nextPageKey = pageKey + pageLength;
         _pagingController.appendPage(items, nextPageKey);
       }
 
       setState(() {
-        resultCount = page.count;
+        resultCount = pageCount;
       });
 
-    } catch (error) {
+    } catch (error, stackTrace) {
       _pagingController.error = error;
+
+      sentryReportError(error, stackTrace);
     }
   }
 
   void _openItem(BuildContext context, int pk) {
-    InvenTreeStockItem().get(context, pk).then((var item) {
+    InvenTreeStockItem().get(pk).then((var item) {
       if (item is InvenTreeStockItem) {
         Navigator.push(context, MaterialPageRoute(builder: (context) => StockDetailWidget(item)));
       }
diff --git a/lib/widget/part_detail.dart b/lib/widget/part_detail.dart
index d28102f8..b13119e8 100644
--- a/lib/widget/part_detail.dart
+++ b/lib/widget/part_detail.dart
@@ -22,7 +22,7 @@ import 'location_display.dart';
 
 class PartDetailWidget extends StatefulWidget {
 
-  PartDetailWidget(this.part, {Key key}) : super(key: key);
+  PartDetailWidget(this.part, {Key? key}) : super(key: key);
 
   final InvenTreePart part;
 
@@ -87,22 +87,22 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
   }
 
   @override
-  Future<void> request(BuildContext context) async {
-    await part.reload(context);
-    await part.getTestTemplates(context);
+  Future<void> request() async {
+    await part.reload();
+    await part.getTestTemplates();
   }
 
   void _toggleStar() async {
 
     if (InvenTreeAPI().checkPermission('part', 'view')) {
-      await part.update(context, values: {"starred": "${!part.starred}"});
+      await part.update(values: {"starred": "${!part.starred}"});
       refresh();
     }
   }
 
   void _savePart(Map<String, String> values) async {
 
-    final bool result = await part.update(context, values: values);
+    final bool result = await part.update(values: values);
 
     if (result) {
       showSnackIcon(L10().partEdited, success: true);
@@ -121,7 +121,11 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
    * Upload image for this Part.
    * Show a SnackBar with upload result.
    */
-  void _uploadImage(File image) async {
+  void _uploadImage(File? image) async {
+
+    if (image == null) {
+      return;
+    }
 
     final result = await part.uploadImage(image);
 
@@ -143,7 +147,7 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
 
   void _selectImage() {
 
-    File _attachment;
+    File? _attachment;
 
     if (!InvenTreeAPI().checkPermission('part', 'change')) {
       return;
@@ -261,7 +265,7 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
     }
 
     // Category information
-    if (part.categoryName != null && part.categoryName.isNotEmpty) {
+    if (part.categoryName.isNotEmpty) {
       tiles.add(
         ListTile(
             title: Text(L10().partCategory),
@@ -269,9 +273,12 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
             leading: FaIcon(FontAwesomeIcons.sitemap),
             onTap: () {
               if (part.categoryId > 0) {
-                InvenTreePartCategory().get(context, part.categoryId).then((var cat) {
-                  Navigator.push(context, MaterialPageRoute(
-                      builder: (context) => CategoryDisplayWidget(cat)));
+                InvenTreePartCategory().get(part.categoryId).then((var cat) {
+
+                  if (cat is InvenTreePartCategory) {
+                    Navigator.push(context, MaterialPageRoute(
+                        builder: (context) => CategoryDisplayWidget(cat)));
+                  }
                 });
               }
             },
@@ -499,7 +506,7 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
           )
         );
       default:
-        return null;
+        return Center();
     }
   }
 
diff --git a/lib/widget/part_notes.dart b/lib/widget/part_notes.dart
index 8b84b640..929cbaa6 100644
--- a/lib/widget/part_notes.dart
+++ b/lib/widget/part_notes.dart
@@ -9,7 +9,7 @@ class PartNotesWidget extends StatefulWidget {
 
   final InvenTreePart part;
 
-  PartNotesWidget(this.part, {Key key}) : super(key: key);
+  PartNotesWidget(this.part, {Key? key}) : super(key: key);
 
   @override
   _PartNotesState createState() => _PartNotesState(part);
diff --git a/lib/widget/refreshable_state.dart b/lib/widget/refreshable_state.dart
index 6a5dc052..d981e6a0 100644
--- a/lib/widget/refreshable_state.dart
+++ b/lib/widget/refreshable_state.dart
@@ -11,7 +11,7 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
   final refreshableKey = GlobalKey<ScaffoldState>();
 
   // Storage for context once "Build" is called
-  BuildContext context;
+  BuildContext? _context;
 
   // Current tab index (used for widgets which display bottom tabs)
   int tabIndex = 0;
@@ -36,7 +36,7 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
 
   void initState() {
     super.initState();
-    WidgetsBinding.instance.addPostFrameCallback((_) => onBuild(context));
+    WidgetsBinding.instance?.addPostFrameCallback((_) => onBuild(_context!));
   }
 
   // Function called after the widget is first build
@@ -45,7 +45,7 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
   }
 
   // Function to request data for this page
-  Future<void> request(BuildContext context) async {
+  Future<void> request() async {
     return;
   }
 
@@ -55,7 +55,7 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
       loading = true;
     });
 
-    await request(context);
+    await request();
 
     setState(() {
       loading = false;
@@ -77,14 +77,16 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
 
   // Function to construct a body (MUST BE PROVIDED)
   Widget getBody(BuildContext context) {
+
+    // Default return is an empty ListView
+    return ListView();
+  }
+
+  Widget? getBottomNavBar(BuildContext context) {
     return null;
   }
 
-  Widget getBottomNavBar(BuildContext context) {
-    return null;
-  }
-
-  Widget getFab(BuildContext context) {
+  Widget? getFab(BuildContext context) {
     return null;
   }
 
@@ -92,7 +94,7 @@ abstract class RefreshableState<T extends StatefulWidget> extends State<T> {
   Widget build(BuildContext context) {
 
     // Save the context for future use
-    this.context = context;
+    _context = context;
 
     return Scaffold(
       key: refreshableKey,
diff --git a/lib/widget/search.dart b/lib/widget/search.dart
index c6b9c0e9..97ccde01 100644
--- a/lib/widget/search.dart
+++ b/lib/widget/search.dart
@@ -15,23 +15,30 @@ import '../api.dart';
 
 // TODO - Refactor duplicate code in this file!
 
-class PartSearchDelegate extends SearchDelegate<InvenTreePart> {
+class PartSearchDelegate extends SearchDelegate<InvenTreePart?> {
 
   final partSearchKey = GlobalKey<ScaffoldState>();
 
   BuildContext context;
 
   // What did we search for last time?
-  String _cachedQuery;
+  String _cachedQuery = "";
 
   bool _searching = false;
 
   // Custom filters for the part search
-  Map<String, String> filters = {};
+  Map<String, String> _filters = {};
 
-  PartSearchDelegate(this.context, {this.filters}) {
-    if (filters == null) {
-      filters = {};
+  PartSearchDelegate(this.context, {Map<String, String> filters = const {}}) {
+
+    // Copy filter values
+    for (String key in filters.keys) {
+
+      String? value = filters[key];
+
+      if (value != null) {
+        _filters[key] = value;
+      }
     }
   }
 
@@ -62,16 +69,15 @@ class PartSearchDelegate extends SearchDelegate<InvenTreePart> {
 
     showResults(context);
 
-    // Enable cascading part search by default
-    filters["cascade"] = "true";
+    _filters["cascade"] = "true";
 
-    final results = await InvenTreePart().search(context, query, filters: filters);
+    final results = await InvenTreePart().search(context, query, filters: _filters);
 
     partResults.clear();
 
     for (int idx = 0; idx < results.length; idx++) {
       if (results[idx] is InvenTreePart) {
-        partResults.add(results[idx]);
+        partResults.add(results[idx] as InvenTreePart);
       }
     }
 
@@ -132,7 +138,7 @@ class PartSearchDelegate extends SearchDelegate<InvenTreePart> {
       ),
       trailing: Text(part.inStockString),
       onTap: () {
-        InvenTreePart().get(context, part.pk).then((var prt) {
+        InvenTreePart().get(part.pk).then((var prt) {
           if (prt is InvenTreePart) {
             Navigator.push(
               context,
@@ -201,22 +207,29 @@ class PartSearchDelegate extends SearchDelegate<InvenTreePart> {
 }
 
 
-class StockSearchDelegate extends SearchDelegate<InvenTreeStockItem> {
+class StockSearchDelegate extends SearchDelegate<InvenTreeStockItem?> {
 
   final stockSearchKey = GlobalKey<ScaffoldState>();
 
   final BuildContext context;
 
-  String _cachedQuery;
+  String _cachedQuery = "";
 
   bool _searching = false;
 
   // Custom filters for the stock item search
-  Map<String, String> filters;
+  Map<String, String> _filters = {};
 
-  StockSearchDelegate(this.context, {this.filters}) {
-    if (filters == null) {
-      filters = {};
+  StockSearchDelegate(this.context, {Map<String, String> filters = const {}}) {
+
+    // Copy filter values
+    for (String key in filters.keys) {
+
+      String? value = filters[key];
+
+      if (value != null) {
+        _filters[key] = value;
+      }
     }
   }
 
@@ -247,16 +260,16 @@ class StockSearchDelegate extends SearchDelegate<InvenTreeStockItem> {
     showResults(context);
 
     // Enable cascading part search by default
-    filters["cascade"] = "true";
+    _filters["cascade"] = "true";
 
     final results = await InvenTreeStockItem().search(
-        context, query, filters: filters);
+        context, query, filters: _filters);
 
     itemResults.clear();
 
     for (int idx = 0; idx < results.length; idx++) {
       if (results[idx] is InvenTreeStockItem) {
-        itemResults.add(results[idx]);
+        itemResults.add(results[idx] as InvenTreeStockItem);
       }
     }
 
@@ -315,7 +328,7 @@ class StockSearchDelegate extends SearchDelegate<InvenTreeStockItem> {
       ),
       trailing: Text(item.serialOrQuantityDisplay()),
       onTap: () {
-        InvenTreeStockItem().get(context, item.pk).then((var it) {
+        InvenTreeStockItem().get(item.pk).then((var it) {
           if (it is InvenTreeStockItem) {
             Navigator.push(
               context,
diff --git a/lib/widget/snacks.dart b/lib/widget/snacks.dart
index 6bba7277..2856cd99 100644
--- a/lib/widget/snacks.dart
+++ b/lib/widget/snacks.dart
@@ -15,14 +15,14 @@ import 'package:one_context/one_context.dart';
 import 'package:InvenTree/l10.dart';
 
 
-void showSnackIcon(String text, {IconData icon, Function onAction, bool success, String actionText}) {
+void showSnackIcon(String text, {IconData? icon, Function()? onAction, bool? success, String? actionText}) {
 
   OneContext().hideCurrentSnackBar();
 
-  Color backgroundColor;
+  Color backgroundColor = Colors.deepOrange;
 
   // Make some selections based on the "success" value
-  if (success == true) {
+  if (success != null && success == true) {
     backgroundColor = Colors.lightGreen;
 
     // Select an icon if we do not have an action
@@ -30,26 +30,21 @@ void showSnackIcon(String text, {IconData icon, Function onAction, bool success,
       icon = FontAwesomeIcons.checkCircle;
     }
 
-  } else if (success == false) {
+  } else if (success != null && success == false) {
     backgroundColor = Colors.deepOrange;
 
     if (icon == null && onAction == null) {
       icon = FontAwesomeIcons.exclamationCircle;
     }
-
   }
 
-  SnackBarAction action;
+  String _action = actionText ?? L10().details;
+
+  SnackBarAction? action;
 
   if (onAction != null) {
-
-    if (actionText == null) {
-      // Default action text
-      actionText = L10().details;
-    }
-
     action = SnackBarAction(
-      label: actionText,
+      label: _action,
       onPressed: onAction,
     );
   }
diff --git a/lib/widget/spinner.dart b/lib/widget/spinner.dart
index 5bab6c4f..eb049a11 100644
--- a/lib/widget/spinner.dart
+++ b/lib/widget/spinner.dart
@@ -4,13 +4,13 @@ import 'package:flutter/cupertino.dart';
 import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 
 class Spinner extends StatefulWidget {
-  final IconData icon;
+  final IconData? icon;
   final Duration duration;
   final Color color;
 
   const Spinner({
     this.color = const Color.fromRGBO(150, 150, 150, 1),
-    Key key,
+    Key? key,
     @required this.icon,
     this.duration = const Duration(milliseconds: 1800),
   }) : super(key: key);
@@ -20,8 +20,8 @@ class Spinner extends StatefulWidget {
 }
 
 class _SpinnerState extends State<Spinner> with SingleTickerProviderStateMixin {
-  AnimationController _controller;
-  Widget _child;
+  AnimationController? _controller;
+  Widget? _child;
 
   @override
   void initState() {
@@ -40,14 +40,14 @@ class _SpinnerState extends State<Spinner> with SingleTickerProviderStateMixin {
 
   @override
   void dispose() {
-    _controller.dispose();
+    _controller!.dispose();
     super.dispose();
   }
 
   @override
   Widget build(BuildContext context) {
     return RotationTransition(
-      turns: _controller,
+      turns: _controller!,
       child: _child,
     );
   }
diff --git a/lib/widget/starred_parts.dart b/lib/widget/starred_parts.dart
index 8d760400..a571b2fe 100644
--- a/lib/widget/starred_parts.dart
+++ b/lib/widget/starred_parts.dart
@@ -14,7 +14,7 @@ import '../api.dart';
 
 class StarredPartWidget extends StatefulWidget {
 
-  StarredPartWidget({Key key}) : super(key: key);
+  StarredPartWidget({Key? key}) : super(key: key);
 
   @override
   _StarredPartState createState() => _StarredPartState();
@@ -29,15 +29,17 @@ class _StarredPartState extends RefreshableState<StarredPartWidget> {
   String getAppBarTitle(BuildContext context) => L10().partsStarred;
 
   @override
-  Future<void> request(BuildContext context) async {
+  Future<void> request() async {
 
-    final parts = await InvenTreePart().list(context, filters: {"starred": "true"});
+    final parts = await InvenTreePart().list(filters: {"starred": "true"});
 
     starredParts.clear();
 
-    for (int idx = 0; idx < parts.length; idx++) {
-      if (parts[idx] is InvenTreePart) {
-        starredParts.add(parts[idx]);
+    if (parts != null) {
+      for (int idx = 0; idx < parts.length; idx++) {
+        if (parts[idx] is InvenTreePart) {
+          starredParts.add(parts[idx] as InvenTreePart);
+        }
       }
     }
   }
@@ -54,7 +56,7 @@ class _StarredPartState extends RefreshableState<StarredPartWidget> {
             height: 40
         ),
         onTap: () {
-          InvenTreePart().get(context, part.pk).then((var prt) {
+          InvenTreePart().get(part.pk).then((var prt) {
             if (prt is InvenTreePart) {
               Navigator.push(
                   context,
diff --git a/lib/widget/stock_detail.dart b/lib/widget/stock_detail.dart
index e96381cb..1682968b 100644
--- a/lib/widget/stock_detail.dart
+++ b/lib/widget/stock_detail.dart
@@ -25,7 +25,7 @@ import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 
 class StockDetailWidget extends StatefulWidget {
 
-  StockDetailWidget(this.item, {Key key}) : super(key: key);
+  StockDetailWidget(this.item, {Key? key}) : super(key: key);
 
   final InvenTreeStockItem item;
 
@@ -77,7 +77,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
   final InvenTreeStockItem item;
 
   // Part object
-  InvenTreePart part;
+  InvenTreePart? part;
 
   @override
   Future<void> onBuild(BuildContext context) async {
@@ -89,14 +89,14 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
   }
 
   @override
-  Future<void> request(BuildContext context) async {
-    await item.reload(context);
+  Future<void> request() async {
+    await item.reload();
 
     // Request part information
-    part = await InvenTreePart().get(context, item.partId);
+    part = await InvenTreePart().get(item.partId) as InvenTreePart;
 
     // Request test results...
-    await item.getTestResults(context);
+    await item.getTestResults();
   }
 
   void _addStock() async {
@@ -227,7 +227,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
 
   void _unassignBarcode(BuildContext context) async {
 
-    final bool result = await item.update(context, values: {'uid': ''});
+    final bool result = await item.update(values: {'uid': ''});
 
     if (result) {
       showSnackIcon(
@@ -245,7 +245,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
   }
 
 
-  void _transferStock(BuildContext context, InvenTreeStockLocation location) async {
+  void _transferStock(InvenTreeStockLocation location) async {
 
     double quantity = double.tryParse(_quantityController.text) ?? item.quantity;
     String notes = _notesController.text;
@@ -264,17 +264,21 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
 
   void _transferStockDialog() async {
 
-    var locations = await InvenTreeStockLocation().list(context);
+    var locations = await InvenTreeStockLocation().list();
     final _selectedController = TextEditingController();
 
-    InvenTreeStockLocation selectedLocation;
+    InvenTreeStockLocation? selectedLocation;
 
     _quantityController.text = "${item.quantityString}";
 
     showFormDialog(L10().transferStock,
         key: _moveStockKey,
         callback: () {
-          _transferStock(context, selectedLocation);
+          var _loc = selectedLocation;
+
+          if (_loc != null) {
+            _transferStock(_loc);
+          }
         },
         fields: <Widget>[
           QuantityField(
@@ -292,7 +296,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
                   )
               ),
               suggestionsCallback: (pattern) async {
-                var suggestions = List<InvenTreeStockLocation>();
+                List<InvenTreeStockLocation> suggestions = [];
 
                 for (var loc in locations) {
                   if (loc.matchAgainstString(pattern)) {
@@ -311,7 +315,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
               },
               onSuggestionSelected: (suggestion) {
                 selectedLocation = suggestion as InvenTreeStockLocation;
-                _selectedController.text = selectedLocation.pathstring;
+                _selectedController.text = selectedLocation!.pathstring;
               },
               onSaved: (value) {
               },
@@ -342,7 +346,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
         ),
         onTap: () {
           if (item.partId > 0) {
-            InvenTreePart().get(context, item.partId).then((var part) {
+            InvenTreePart().get(item.partId).then((var part) {
               if (part is InvenTreePart) {
                 Navigator.push(context, MaterialPageRoute(builder: (context) => PartDetailWidget(part)));
               }
@@ -397,9 +401,12 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
             leading: FaIcon(FontAwesomeIcons.mapMarkerAlt),
             onTap: () {
               if (item.locationId > 0) {
-                InvenTreeStockLocation().get(context, item.locationId).then((var loc) {
-                  Navigator.push(context, MaterialPageRoute(
-                      builder: (context) => LocationDisplayWidget(loc)));
+                InvenTreeStockLocation().get(item.locationId).then((var loc) {
+
+                  if (loc is InvenTreeStockLocation) {
+                    Navigator.push(context, MaterialPageRoute(
+                        builder: (context) => LocationDisplayWidget(loc)));
+                  }
                 });
               }
             },
@@ -442,7 +449,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
       );
     }
 
-    if ((item.testResultCount > 0) || (part != null && part.isTrackable)) {
+    if ((item.testResultCount > 0) || (part?.isTrackable ?? false)) {
       tiles.add(
           ListTile(
               title: Text(L10().testResults),
@@ -641,7 +648,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
           ).toList()
         );
       default:
-        return null;
+        return ListView();
     }
   }
 
diff --git a/lib/widget/stock_item_test_results.dart b/lib/widget/stock_item_test_results.dart
index c9c6cefe..4015742e 100644
--- a/lib/widget/stock_item_test_results.dart
+++ b/lib/widget/stock_item_test_results.dart
@@ -19,7 +19,7 @@ import 'package:font_awesome_flutter/font_awesome_flutter.dart';
 
 class StockItemTestResultsWidget extends StatefulWidget {
 
-  StockItemTestResultsWidget(this.item, {Key key}) : super(key: key);
+  StockItemTestResultsWidget(this.item, {Key? key}) : super(key: key);
 
   final InvenTreeStockItem item;
 
@@ -36,16 +36,16 @@ class _StockItemTestResultDisplayState extends RefreshableState<StockItemTestRes
   String getAppBarTitle(BuildContext context) => L10().testResults;
 
   @override
-  Future<void> request(BuildContext context) async {
-    await item.getTestTemplates(context);
-    await item.getTestResults(context);
+  Future<void> request() async {
+    await item.getTestTemplates();
+    await item.getTestResults();
   }
 
   final InvenTreeStockItem item;
 
   _StockItemTestResultDisplayState(this.item);
 
-  void uploadTestResult(String name, bool result, String value, String notes, File attachment) async {
+  void uploadTestResult(String name, bool result, String value, String notes, File? attachment) async {
 
     final success = await item.uploadTestResult(
       context, name, result,
@@ -64,11 +64,11 @@ class _StockItemTestResultDisplayState extends RefreshableState<StockItemTestRes
 
   void addTestResult({String name = '', bool nameIsEditable = true, bool result = false, String value = '', bool valueRequired = false, bool attachmentRequired = false}) async  {
 
-    String _name;
-    bool _result;
-    String _value;
-    String _notes;
-    File _attachment;
+    String _name = "";
+    bool _result = false;
+    String _value = "";
+    String _notes = "";
+    File? _attachment;
 
     showFormDialog(L10().testResultAdd,
       key: _addResultKey,
@@ -80,21 +80,21 @@ class _StockItemTestResultDisplayState extends RefreshableState<StockItemTestRes
           label: L10().testName,
           initial: name,
           isEnabled: nameIsEditable,
-          onSaved: (value) => _name = value,
+          onSaved: (value) => _name = value ?? '',
         ),
         CheckBoxField(
           label: L10().result,
           hint: L10().testPassedOrFailed,
           initial: true,
-          onSaved: (value) => _result = value,
+          onSaved: (value) => _result = value ?? false,
         ),
         StringField(
           label: L10().value,
           initial: value,
           allowEmpty: true,
-          onSaved: (value) => _value = value,
+          onSaved: (value) => _value = value ?? '',
           validator: (String value) {
-            if (valueRequired && (value == null || value.isEmpty)) {
+            if (valueRequired && value.isEmpty) {
               return L10().valueRequired;
             }
             return null;
@@ -109,7 +109,7 @@ class _StockItemTestResultDisplayState extends RefreshableState<StockItemTestRes
         StringField(
           allowEmpty: true,
           label: L10().notes,
-          onSaved: (value) => _notes = value,
+          onSaved: (value) => _notes = value ?? '',
         ),
       ]
     );
@@ -202,10 +202,11 @@ class _StockItemTestResultDisplayState extends RefreshableState<StockItemTestRes
     for (var item in results) {
 
       bool _required = false;
-      String _test;
-      bool _result = null;
-      String _value;
-      String _notes;
+      String _test = "";
+      bool _result = false;
+      String _value = "";
+      String _notes = "";
+
       FaIcon _icon = FaIcon(FontAwesomeIcons.questionCircle, color: Color.fromRGBO(0, 0, 250, 1));
       bool _valueRequired = false;
       bool _attachmentRequired = false;
diff --git a/lib/widget/stock_notes.dart b/lib/widget/stock_notes.dart
index 50aad3e2..b07159c7 100644
--- a/lib/widget/stock_notes.dart
+++ b/lib/widget/stock_notes.dart
@@ -10,7 +10,7 @@ class StockNotesWidget extends StatefulWidget {
 
   final InvenTreeStockItem item;
 
-  StockNotesWidget(this.item, {Key key}) : super(key: key);
+  StockNotesWidget(this.item, {Key? key}) : super(key: key);
 
   @override
   _StockNotesState createState() => _StockNotesState(item);
diff --git a/pubspec.lock b/pubspec.lock
index c1c9d3d1..9fd00be7 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -29,6 +29,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.19.0"
+  back_button_interceptor:
+    dependency: transitive
+    description:
+      name: back_button_interceptor
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.0.1"
   boolean_selector:
     dependency: transitive
     description:
@@ -42,7 +49,7 @@ packages:
       name: cached_network_image
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0"
+    version: "3.0.0"
   camera:
     dependency: "direct main"
     description:
@@ -105,7 +112,7 @@ packages:
       name: cupertino_icons
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.3"
+    version: "1.0.3"
   device_info:
     dependency: "direct main"
     description:
@@ -152,21 +159,35 @@ packages:
       name: flutter_blurhash
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.0"
+    version: "0.6.0"
   flutter_cache_manager:
     dependency: transitive
     description:
       name: flutter_cache_manager
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.2"
+    version: "3.1.2"
   flutter_keyboard_visibility:
     dependency: transitive
     description:
       name: flutter_keyboard_visibility
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.3.0"
+    version: "5.0.2"
+  flutter_keyboard_visibility_platform_interface:
+    dependency: transitive
+    description:
+      name: flutter_keyboard_visibility_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
+  flutter_keyboard_visibility_web:
+    dependency: transitive
+    description:
+      name: flutter_keyboard_visibility_web
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   flutter_launcher_icons:
     dependency: "direct dev"
     description:
@@ -199,7 +220,7 @@ packages:
       name: flutter_speed_dial
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.5"
+    version: "3.0.5"
   flutter_test:
     dependency: "direct dev"
     description: flutter
@@ -211,7 +232,7 @@ packages:
       name: flutter_typeahead
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.8"
+    version: "3.1.3"
   flutter_web_plugins:
     dependency: transitive
     description: flutter
@@ -223,7 +244,7 @@ packages:
       name: font_awesome_flutter
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "8.11.0"
+    version: "9.1.0"
   http:
     dependency: "direct main"
     description:
@@ -272,7 +293,7 @@ packages:
       name: infinite_scroll_pagination
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.3.0"
+    version: "3.1.0"
   intl:
     dependency: "direct main"
     description:
@@ -314,14 +335,14 @@ packages:
       name: octo_image
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.0"
+    version: "1.0.0+1"
   one_context:
     dependency: "direct main"
     description:
       name: one_context
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.0"
+    version: "1.1.0"
   package_info:
     dependency: "direct main"
     description:
@@ -454,7 +475,7 @@ packages:
       name: qr_code_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.5"
+    version: "0.5.1"
   quiver:
     dependency: transitive
     description:
@@ -468,14 +489,14 @@ packages:
       name: rxdart
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.25.0"
+    version: "0.27.1"
   sembast:
     dependency: "direct main"
     description:
       name: sembast
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.4.9"
+    version: "3.1.0+2"
   sentry:
     dependency: transitive
     description:
@@ -496,28 +517,42 @@ packages:
       name: shared_preferences
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.7+3"
+    version: "2.0.6"
+  shared_preferences_linux:
+    dependency: transitive
+    description:
+      name: shared_preferences_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   shared_preferences_macos:
     dependency: transitive
     description:
       name: shared_preferences_macos
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.1+11"
+    version: "2.0.0"
   shared_preferences_platform_interface:
     dependency: transitive
     description:
       name: shared_preferences_platform_interface
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "2.0.0"
   shared_preferences_web:
     dependency: transitive
     description:
       name: shared_preferences_web
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.2+7"
+    version: "2.0.0"
+  shared_preferences_windows:
+    dependency: transitive
+    description:
+      name: shared_preferences_windows
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -529,7 +564,7 @@ packages:
       name: sliver_tools
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.10+1"
+    version: "0.2.5"
   source_span:
     dependency: transitive
     description:
@@ -543,14 +578,14 @@ packages:
       name: sqflite
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.2+3"
+    version: "2.0.0+3"
   sqflite_common:
     dependency: transitive
     description:
       name: sqflite_common
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.3+1"
+    version: "2.0.0+2"
   stack_trace:
     dependency: transitive
     description:
@@ -585,7 +620,7 @@ packages:
       name: synchronized
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.0+2"
+    version: "3.0.0"
   term_glyph:
     dependency: transitive
     description:
diff --git a/pubspec.yaml b/pubspec.yaml
index 6208add5..b3f634e2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -7,10 +7,10 @@ description: InvenTree stock management
 # In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
 # Read more about iOS versioning at
 # https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
-version: 0.2.5+13
+version: 0.2.6+14
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
@@ -21,25 +21,25 @@ dependencies:
 
   intl: ^0.17.0
 
-  cupertino_icons: ^0.1.3
+  cupertino_icons: ^1.0.3
   http: ^0.13.0
-  cached_network_image: ^2.5.0
-  qr_code_scanner: ^0.3.5                 # Barcode scanning
+  cached_network_image: ^3.0.0            # Download and cache remote images
+  qr_code_scanner: ^0.5.1                 # Barcode scanning
   package_info: ^2.0.0                    # App information introspection
   device_info: ^2.0.0                     # Information about the device
-  font_awesome_flutter: ^8.8.1            # FontAwesome icon set
-  flutter_speed_dial: ^1.2.5              # FAB menu elements
-  sentry_flutter: 5.0.0                  # Error reporting
-  flutter_typeahead: ^1.8.1               # Auto-complete input field
+  font_awesome_flutter: ^9.1.0            # FontAwesome icon set
+  flutter_speed_dial: ^3.0.5              # FAB menu elements
+  sentry_flutter: 5.0.0                   # Error reporting
+  flutter_typeahead: ^3.1.0               # Auto-complete input field
   image_picker: ^0.8.0                    # Select or take photos
-  url_launcher: 6.0.0                   # Open link in system browser
+  url_launcher: 6.0.0                     # Open link in system browser
   flutter_markdown: ^0.6.2                # Rendering markdown
   camera:                                 # Camera
-  path_provider: 2.0.1 #^1.6.28                  # Local file storage
-  sembast: ^2.4.9                         # NoSQL data storage
-  one_context: ^0.5.0                     # Dialogs without requiring context
-  infinite_scroll_pagination: ^2.3.0      # Let the server do all the work!
-  audioplayers: ^0.19.0
+  path_provider: 2.0.1                    # Local file storage
+  sembast: ^3.1.0+2                       # NoSQL data storage
+  one_context: ^1.1.0                     # Dialogs without requiring context
+  infinite_scroll_pagination: ^3.1.0      # Let the server do all the work!
+  audioplayers: ^0.19.0                   # Play audio files
   path:
 
 dev_dependencies: