diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 46587b8..9d86f5d 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -6,9 +6,9 @@ name: CI
 # events but only for the master branch
 on:
   push:
-    branches: [ master ]
+    branches: [ master, feature/null-safety ]
   pull_request:
-    branches: [ master ]
+    branches: [ master, feature/null-safety ]
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
@@ -20,7 +20,9 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       - uses: actions/checkout@v2
-      - uses: subosito/flutter-action@v1.3.0
+      - uses: subosito/flutter-action@v1.4.0
+        with:
+          channel: beta
       - name: Install Dependencies
         run: flutter packages get
       - name: Format
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 213765d..9df067d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+## [2.0.0-nullsafety.1] - 28.03.2021
+
+* Refactor code smells 
+
+## [2.0.0-nullsafety.0] - 28.03.2021
+
+* Sound null-safety
+
 ## [1.3.0] - 15.11.2020
 
 * Update dependencies
diff --git a/LICENSE b/LICENSE
index 2d752e3..e653f4a 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020 Dimitrios Begnis
+Copyright (c) 2021 Dimitrios Begnis
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index 504eda1..77cfa9a 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ The list will be scrolled to the end in the initial state and therefore scrollin
  Add the package to your pubspec.yaml:
 
  ```yaml
- sticky_grouped_list: ^1.3.0
+ sticky_grouped_list: ^2.0.0-nullsafety.1
  ```
  
  In your dart file, import the library:
diff --git a/example/lib/chatExample.dart b/example/lib/chatExample.dart
index b9427c8..e97e468 100644
--- a/example/lib/chatExample.dart
+++ b/example/lib/chatExample.dart
@@ -4,7 +4,7 @@ import 'package:sticky_grouped_list/sticky_grouped_list.dart';
 
 void main() => runApp(MyApp());
 
-List _elements = <Element>[
+List<Element> _elements = <Element>[
   Element(DateTime(2020, 6, 24, 9, 25), 'Hello how are you?'),
   Element(DateTime(2020, 6, 24, 9, 36), 'Fine and what about you?', true),
   Element(DateTime(2020, 6, 24, 9, 39), 'I am fine too'),
@@ -60,7 +60,7 @@ class MyApp extends StatelessWidget {
                       decoration: BoxDecoration(
                         color: Colors.blue[300],
                         border: Border.all(
-                          color: Colors.blue[300],
+                          color: Colors.blue[300]!,
                         ),
                         borderRadius: BorderRadius.all(Radius.circular(20.0)),
                       ),
diff --git a/example/lib/example.dart b/example/lib/example.dart
index cbb00e6..b42406f 100644
--- a/example/lib/example.dart
+++ b/example/lib/example.dart
@@ -3,7 +3,7 @@ import 'package:sticky_grouped_list/sticky_grouped_list.dart';
 
 void main() => runApp(MyApp());
 
-List _elements = <Element>[
+List<Element> _elements = <Element>[
   Element(DateTime(2020, 6, 24, 18), 'Got to gym', Icons.fitness_center),
   Element(DateTime(2020, 6, 24, 9), 'Work', Icons.work),
   Element(DateTime(2020, 6, 25, 8), 'Buy groceries', Icons.shopping_basket),
@@ -52,7 +52,7 @@ class MyApp extends StatelessWidget {
                 decoration: BoxDecoration(
                   color: Colors.blue[300],
                   border: Border.all(
-                    color: Colors.blue[300],
+                    color: Colors.blue[300]!,
                   ),
                   borderRadius: BorderRadius.all(Radius.circular(20.0)),
                 ),
diff --git a/example/pubspec.lock b/example/pubspec.lock
index dbb9cfd..f57fcc1 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -7,49 +7,49 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0-nullsafety.1"
+    version: "2.5.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   characters:
     dependency: transitive
     description:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.3"
+    version: "1.15.0"
   fake_async:
     dependency: transitive
     description:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -66,35 +66,35 @@ packages:
       name: intl
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.16.1"
+    version: "0.17.0"
   matcher:
     dependency: transitive
     description:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10-nullsafety.1"
+    version: "0.12.10"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.1"
+    version: "1.8.0"
   scrollable_positioned_list:
     dependency: transitive
     description:
       name: scrollable_positioned_list
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.8"
+    version: "0.2.0-nullsafety.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -106,63 +106,63 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.2"
+    version: "1.8.0"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.1"
+    version: "1.10.0"
   sticky_grouped_list:
     dependency: "direct main"
     description:
       path: ".."
       relative: true
     source: path
-    version: "1.3.0"
+    version: "2.0.0-nullsafety.1"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19-nullsafety.2"
+    version: "0.2.19"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0"
 sdks:
-  dart: ">=2.10.0-110 <2.11.0"
-  flutter: ">=1.12.13+hotfix.5 <2.0.0"
+  dart: ">=2.12.0 <3.0.0"
+  flutter: ">=1.13.8"
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index c6214f2..bc7233e 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -1,56 +1,18 @@
 name: example
 description: A new Flutter package project.
 version: 0.0.1
-author:
-homepage:
+publish_to: 'none' 
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
   sticky_grouped_list:
     path: ../
-  intl: ^0.16.1
+  intl: ^0.17.0
 
 dev_dependencies:
   flutter_test:
-    sdk: flutter
-
-# For information on the generic Dart part of this file, see the
-# following page: https://dart.dev/tools/pub/pubspec
-
-# The following section is specific to Flutter.
-flutter:
-
-  # To add assets to your package, add an assets section, like this:
-  # assets:
-  #   - images/a_dot_burr.jpeg
-  #   - images/a_dot_ham.jpeg
-  #
-  # For details regarding assets in packages, see
-  # https://flutter.dev/assets-and-images/#from-packages
-  #
-  # An image asset can refer to one or more resolution-specific "variants", see
-  # https://flutter.dev/assets-and-images/#resolution-aware.
-
-  # To add custom fonts to your package, add a fonts section here,
-  # in this "flutter" section. Each entry in this list should have a
-  # "family" key with the font family name, and a "fonts" key with a
-  # list giving the asset and other descriptors for the font. For
-  # example:
-  # fonts:
-  #   - family: Schyler
-  #     fonts:
-  #       - asset: fonts/Schyler-Regular.ttf
-  #       - asset: fonts/Schyler-Italic.ttf
-  #         style: italic
-  #   - family: Trajan Pro
-  #     fonts:
-  #       - asset: fonts/TrajanPro.ttf
-  #       - asset: fonts/TrajanPro_Bold.ttf
-  #         weight: 700
-  #
-  # For details regarding fonts in packages, see
-  # https://flutter.dev/custom-fonts/#from-packages
+    sdk: flutter
\ No newline at end of file
diff --git a/lib/sticky_grouped_list.dart b/lib/sticky_grouped_list.dart
index b96195c..dcbdf3f 100644
--- a/lib/sticky_grouped_list.dart
+++ b/lib/sticky_grouped_list.dart
@@ -10,7 +10,7 @@ import 'package:scrollable_positioned_list/scrollable_positioned_list.dart';
 ///
 /// See [ScrollablePositionedList]
 class StickyGroupedListView<T, E> extends StatefulWidget {
-  final Key key;
+  final Key? key;
 
   /// Items of which [itemBuilder] or [indexedItemBuilder] produce the list.
   final List<T> elements;
@@ -25,13 +25,13 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
   ///
   /// If not set groups will be sorted with their natural sorting order or their
   /// specific [Comparable] implementation.
-  final int Function(E value1, E value2) groupComparator;
+  final int Function(E value1, E value2)? groupComparator;
 
   /// Can be used to define a custom sorting for the elements inside each group.
   ///
   /// If not set elements will be sorted with their natural sorting order or
   /// their specific [Comparable] implementation.
-  final int Function(T element1, T element2) itemComparator;
+  final int Function(T element1, T element2)? itemComparator;
 
   /// Called to build group separators for each group.
   /// element is always the first element of the group.
@@ -39,11 +39,11 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
 
   /// Called to build children for the list with
   /// 0 <= element < elements.length.
-  final Widget Function(BuildContext context, T element) itemBuilder;
+  final Widget Function(BuildContext context, T element)? itemBuilder;
 
   /// Called to build children for the list with
   /// 0 <= element, index < elements.length
-  final Widget Function(BuildContext context, T element, int index)
+  final Widget Function(BuildContext context, T element, int index)?
       indexedItemBuilder;
 
   /// Whether the sorting of the list is ascending or descending.
@@ -62,10 +62,10 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
   final Color stickyHeaderBackgroundColor;
 
   /// Controller for jumping or scrolling to an item.
-  final GroupedItemScrollController itemScrollController;
+  final GroupedItemScrollController? itemScrollController;
 
   /// Notifier that reports the items laid out in the list after each frame.
-  final ItemPositionsListener itemPositionsListener;
+  final ItemPositionsListener? itemPositionsListener;
 
   /// The axis along which the scroll view scrolls.
   ///
@@ -75,10 +75,10 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
   /// How the scroll view should respond to user input.
   ///
   /// See [ScrollView.physics].
-  final ScrollPhysics physics;
+  final ScrollPhysics? physics;
 
   /// The amount of space by which to inset the children.
-  final EdgeInsetsGeometry padding;
+  final EdgeInsets? padding;
 
   /// Whether the view scrolls in the reading direction.
   ///
@@ -109,12 +109,12 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
   /// scrolls, so using the [ScrollController.scrollTo] method may result
   /// in builds of widgets that would otherwise already be built in the
   /// cache extent.
-  final double minCacheExtent;
+  final double? minCacheExtent;
 
   /// The number of children that will contribute semantic information.
   ///
   /// See [ScrollView.semanticChildCount] for more information.
-  final int semanticChildCount;
+  final int? semanticChildCount;
 
   /// Index of an item to initially align within the viewport.
   final int initialScrollIndex;
@@ -125,18 +125,18 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
 
   /// Creates a [StickyGroupedListView].
   StickyGroupedListView({
-    @required this.elements,
-    @required this.groupBy,
-    @required this.groupSeparatorBuilder,
+    this.key,
+    required this.elements,
+    required this.groupBy,
+    required this.groupSeparatorBuilder,
     this.groupComparator,
     this.itemBuilder,
     this.indexedItemBuilder,
     this.itemComparator,
-    this.order,
+    this.order = StickyGroupedListOrder.ASC,
     this.separator = const SizedBox.shrink(),
     this.floatingHeader = false,
     this.stickyHeaderBackgroundColor = const Color(0xffF7F7F7),
-    this.key,
     this.scrollDirection = Axis.vertical,
     this.itemScrollController,
     this.itemPositionsListener,
@@ -150,7 +150,8 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
     this.semanticChildCount,
     this.initialAlignment = 0,
     this.initialScrollIndex = 0,
-  }) : super(key: key);
+  })  : assert(itemBuilder != null || indexedItemBuilder != null),
+        super(key: key);
 
   @override
   State<StatefulWidget> createState() => _StickyGroupedListViewState<T, E>();
@@ -159,16 +160,16 @@ class StickyGroupedListView<T, E> extends StatefulWidget {
 class _StickyGroupedListViewState<T, E>
     extends State<StickyGroupedListView<T, E>> {
   StreamController<int> _streamController = StreamController<int>();
-  ItemPositionsListener _listener;
-  GroupedItemScrollController _controller;
-  GlobalKey _groupHeaderKey;
+  late ItemPositionsListener _listener;
+  late GroupedItemScrollController _controller;
+  GlobalKey? _groupHeaderKey;
   List<T> _sortedElements = [];
   GlobalKey _key = GlobalKey();
   int _topElementIndex = 0;
-  RenderBox _headerBox;
-  RenderBox _listBox;
-  double _headerDimension;
-  bool Function(int) _isSeparator;
+  RenderBox? _headerBox;
+  RenderBox? _listBox;
+  double? _headerDimension;
+  bool Function(int)? _isSeparator;
 
   @override
   void initState() {
@@ -223,7 +224,7 @@ class _StickyGroupedListViewState<T, E>
               );
             }
 
-            if (_isSeparator(index)) {
+            if (_isSeparator!(index)) {
               E curr = widget.groupBy(_sortedElements[actualIndex]);
               E prev = widget.groupBy(
                   _sortedElements[actualIndex + (widget.reverse ? 1 : -1)]);
@@ -239,7 +240,7 @@ class _StickyGroupedListViewState<T, E>
         StreamBuilder<int>(
           stream: _streamController.stream,
           initialData: _topElementIndex,
-          builder: (_, snapshot) => _showFixedGroupHeader(snapshot.data),
+          builder: (_, snapshot) => _showFixedGroupHeader(snapshot.data!),
         )
       ],
     );
@@ -247,16 +248,17 @@ class _StickyGroupedListViewState<T, E>
 
   Widget _buildItem(context, int actualIndex) {
     return widget.indexedItemBuilder == null
-        ? widget.itemBuilder(context, _sortedElements[actualIndex])
-        : widget.indexedItemBuilder(
+        ? widget.itemBuilder!(context, _sortedElements[actualIndex])
+        : widget.indexedItemBuilder!(
             context, _sortedElements[actualIndex], actualIndex);
   }
 
   _positionListener() {
-    _headerBox ??= _groupHeaderKey?.currentContext?.findRenderObject();
-    double headerHeight = _headerBox?.size?.height ?? 0;
-    _listBox ??= _key?.currentContext?.findRenderObject();
-    double height = _listBox?.size?.height ?? 0;
+    _headerBox ??=
+        _groupHeaderKey?.currentContext?.findRenderObject() as RenderBox?;
+    double headerHeight = _headerBox?.size.height ?? 0;
+    _listBox ??= _key.currentContext?.findRenderObject() as RenderBox?;
+    double height = _listBox?.size.height ?? 0;
     _headerDimension = headerHeight / height;
 
     ItemPosition reducePositions(ItemPosition pos, ItemPosition current) {
@@ -268,11 +270,11 @@ class _StickyGroupedListViewState<T, E>
 
     ItemPosition currentItem = _listener.itemPositions.value
         .where((ItemPosition position) =>
-            !_isSeparator(position.index) &&
-            position.itemTrailingEdge > _headerDimension)
+            !_isSeparator!(position.index) &&
+            position.itemTrailingEdge > _headerDimension!)
         .reduce(reducePositions);
 
-    int index = (currentItem?.index ?? 0) ~/ 2;
+    int index = currentItem.index ~/ 2;
     if (_topElementIndex != index) {
       E curr = widget.groupBy(_sortedElements[index]);
       E prev = widget.groupBy(_sortedElements[_topElementIndex]);
@@ -291,7 +293,7 @@ class _StickyGroupedListViewState<T, E>
         // compare groups
         if (widget.groupComparator != null) {
           compareResult =
-              widget.groupComparator(widget.groupBy(e1), widget.groupBy(e2));
+              widget.groupComparator!(widget.groupBy(e1), widget.groupBy(e2));
         } else if (widget.groupBy(e1) is Comparable) {
           compareResult = (widget.groupBy(e1) as Comparable)
               .compareTo(widget.groupBy(e2) as Comparable);
@@ -299,7 +301,7 @@ class _StickyGroupedListViewState<T, E>
         // compare elements inside group
         if ((compareResult == null || compareResult == 0)) {
           if (widget.itemComparator != null) {
-            compareResult = widget.itemComparator(e1, e2);
+            compareResult = widget.itemComparator!(e1, e2);
           } else if (e1 is Comparable) {
             compareResult = e1.compareTo(e2);
           }
@@ -332,7 +334,7 @@ class _StickyGroupedListViewState<T, E>
 ///
 /// See [ItemScrollController].
 class GroupedItemScrollController extends ItemScrollController {
-  _StickyGroupedListViewState _stickyGroupedListViewState;
+  _StickyGroupedListViewState? _stickyGroupedListViewState;
 
   /// Jumps to the element at [index]. The element will be placed under the
   /// group header.
@@ -341,7 +343,7 @@ class GroupedItemScrollController extends ItemScrollController {
   /// See [ItemScrollController.jumpTo]
   @override
   void jumpTo(
-      {@required int index,
+      {required int index,
       double alignment = 0,
       bool automaticAlignment = true}) {
     if (automaticAlignment) {
@@ -356,20 +358,24 @@ class GroupedItemScrollController extends ItemScrollController {
   ///
   /// See [ItemScrollController.scrollTo]
   @override
-  Future<void> scrollTo(
-      {@required int index,
-      double alignment = 0,
-      bool automaticAlignment = true,
-      @required Duration duration,
-      Curve curve = Curves.linear}) {
+  Future<void> scrollTo({
+    required int index,
+    double alignment = 0,
+    bool automaticAlignment = true,
+    required Duration duration,
+    Curve curve = Curves.linear,
+    List<double> opacityAnimationWeights = const [40, 20, 40],
+  }) {
     if (automaticAlignment) {
       alignment = _stickyGroupedListViewState?._headerDimension ?? alignment;
     }
     return super.scrollTo(
-        index: index * 2 + 1,
-        alignment: alignment,
-        duration: duration,
-        curve: curve);
+      index: index * 2 + 1,
+      alignment: alignment,
+      duration: duration,
+      curve: curve,
+      opacityAnimationWeights: opacityAnimationWeights,
+    );
   }
 
   void _bind(_StickyGroupedListViewState stickyGroupedListViewState) {
diff --git a/pubspec.lock b/pubspec.lock
index 3825d94..623daa7 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -7,49 +7,49 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.5.0-nullsafety.1"
+    version: "2.5.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   characters:
     dependency: transitive
     description:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.3"
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   clock:
     dependency: transitive
     description:
       name: clock
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   collection:
     dependency: transitive
     description:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0-nullsafety.3"
+    version: "1.15.0"
   fake_async:
     dependency: transitive
     description:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -66,28 +66,28 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10-nullsafety.1"
+    version: "0.12.10"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.1"
+    version: "1.8.0"
   scrollable_positioned_list:
     dependency: "direct main"
     description:
       name: scrollable_positioned_list
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.8"
+    version: "0.2.0-nullsafety.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -99,56 +99,56 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0-nullsafety.2"
+    version: "1.8.0"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.10.0-nullsafety.1"
+    version: "1.10.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.1"
+    version: "2.1.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.1"
+    version: "1.1.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0-nullsafety.1"
+    version: "1.2.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.19-nullsafety.2"
+    version: "0.2.19"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0-nullsafety.3"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0-nullsafety.3"
+    version: "2.1.0"
 sdks:
-  dart: ">=2.10.0-110 <2.11.0"
-  flutter: ">=1.12.13+hotfix.5 <2.0.0"
+  dart: ">=2.12.0 <3.0.0"
+  flutter: ">=1.13.8"
diff --git a/pubspec.yaml b/pubspec.yaml
index 3efb11e..a3ced0d 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,54 +1,17 @@
 name: sticky_grouped_list
 description: A ScrollablePositionedList where the list items can be grouped into sections.
-version: 1.3.0
+version: 2.0.0-nullsafety.1
 homepage: https://begnis.dev
 repository: https://github.com/Dimibe/sticky_grouped_list
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  scrollable_positioned_list: ^0.1.8
+  scrollable_positioned_list: ^0.2.0-nullsafety.0
 
 dev_dependencies:
   flutter_test:
-    sdk: flutter
-
-# For information on the generic Dart part of this file, see the
-# following page: https://dart.dev/tools/pub/pubspec
-
-# The following section is specific to Flutter.
-flutter:
-
-  # To add assets to your package, add an assets section, like this:
-  # assets:
-  #   - images/a_dot_burr.jpeg
-  #   - images/a_dot_ham.jpeg
-  #
-  # For details regarding assets in packages, see
-  # https://flutter.dev/assets-and-images/#from-packages
-  #
-  # An image asset can refer to one or more resolution-specific "variants", see
-  # https://flutter.dev/assets-and-images/#resolution-aware.
-
-  # To add custom fonts to your package, add a fonts section here,
-  # in this "flutter" section. Each entry in this list should have a
-  # "family" key with the font family name, and a "fonts" key with a
-  # list giving the asset and other descriptors for the font. For
-  # example:
-  # fonts:
-  #   - family: Schyler
-  #     fonts:
-  #       - asset: fonts/Schyler-Regular.ttf
-  #       - asset: fonts/Schyler-Italic.ttf
-  #         style: italic
-  #   - family: Trajan Pro
-  #     fonts:
-  #       - asset: fonts/TrajanPro.ttf
-  #       - asset: fonts/TrajanPro_Bold.ttf
-  #         weight: 700
-  #
-  # For details regarding fonts in packages, see
-  # https://flutter.dev/custom-fonts/#from-packages
+    sdk: flutter
\ No newline at end of file
diff --git a/test/sticky_grouped_list_test.dart b/test/sticky_grouped_list_test.dart
index d3059d9..2a17057 100644
--- a/test/sticky_grouped_list_test.dart
+++ b/test/sticky_grouped_list_test.dart
@@ -21,11 +21,11 @@ void main() {
       MaterialApp(
         home: Scaffold(
           body: StickyGroupedListView(
-            groupBy: (element) => element['group'],
+            groupBy: (dynamic element) => element['group'],
             elements: _elements,
             order: StickyGroupedListOrder.DESC,
             groupSeparatorBuilder: _buildGroupSeperator,
-            itemBuilder: (context, element) => Text(element['name']),
+            itemBuilder: (context, dynamic element) => Text(element['name']),
           ),
         ),
       ),
@@ -43,10 +43,10 @@ void main() {
       MaterialApp(
         home: Scaffold(
           body: StickyGroupedListView(
-            groupBy: (element) => element['group'],
+            groupBy: (dynamic element) => element['group'],
             elements: [],
             groupSeparatorBuilder: _buildGroupSeperator,
-            itemBuilder: (context, element) => Text(element['name']),
+            itemBuilder: (context, dynamic element) => Text(element['name']),
           ),
         ),
       ),
@@ -59,10 +59,10 @@ void main() {
       MaterialApp(
         home: Scaffold(
           body: StickyGroupedListView(
-            groupBy: (element) => element['group'],
+            groupBy: (dynamic element) => element['group'],
             elements: _elements,
             groupSeparatorBuilder: _buildGroupSeperator,
-            itemBuilder: (context, element) => Text(element['name']),
+            itemBuilder: (context, dynamic element) => Text(element['name']),
           ),
         ),
       ),