diff --git a/README.md b/README.md
index aab144e..d100513 100644
--- a/README.md
+++ b/README.md
@@ -9,13 +9,17 @@ Each row show a hour and each column show a day but you can change the title of
 
 ## Screenshots
 
-| Mobile                                 | Dark                                    |
-| -------------------------------------- | --------------------------------------- |
-| ![Notification](screenshot/Mobile.gif) | ![Attached](screenshot/darkMobile.jpg) |
+| Mobile                           | Dark                               |
+| -------------------------------- | ---------------------------------- |
+| ![Mobile](screenshot/Mobile.gif) | ![Dark](screenshot/darkMobile.jpg) |
 
-| Desktop                                 | Web                             |
-| --------------------------------------- | ------------------------------- |
-| ![Notification](screenshot/Desktop.gif) | ![Attached](screenshot/Web.gif) |
+| Desktop                            | Web                        |
+| ---------------------------------- | -------------------------- |
+| ![Desktop](screenshot/Desktop.gif) | ![Web](screenshot/Web.gif) |
+
+## Demo
+
+You can see web demo here: [https://jamalianpour.github.io/time_planner_demo](https://jamalianpour.github.io/time_planner_demo)
 
 ## Usage
 
diff --git a/example/lib/main.dart b/example/lib/main.dart
index cbc31f8..c4e5f0e 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -22,7 +22,7 @@ class MyApp extends StatelessWidget {
 }
 
 class MyHomePage extends StatefulWidget {
-  MyHomePage({Key key, this.title}) : super(key: key);
+  MyHomePage({Key? key, required this.title}) : super(key: key);
 
   final String title;
 
@@ -34,7 +34,7 @@ class _MyHomePageState extends State<MyHomePage> {
   List<TimePlannerTask> tasks = [];
 
   void _addObject(BuildContext context) {
-    List<Color> colors = [
+    List<Color?> colors = [
       Colors.purple,
       Colors.blue,
       Colors.green,
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index a2e397f..c735763 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -4,7 +4,7 @@ description: An example for time planner
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
diff --git a/pubspec.yaml b/pubspec.yaml
index 4aad231..cfaf970 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -6,7 +6,7 @@ homepage: https://github.com/Jamalianpour/time_planner
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=1.17.0 <2.0.0"
+  flutter: ">=1.17.0"
 
 dependencies:
   flutter: