diff --git a/draggable_borderless/pubspec.yaml b/draggable_borderless/pubspec.yaml
index 8776da3..33a4064 100644
--- a/draggable_borderless/pubspec.yaml
+++ b/draggable_borderless/pubspec.yaml
@@ -14,7 +14,7 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.2.0 <3.0.0"
+  sdk: "<4.0.0"
 
 dependencies:
   flutter:
diff --git a/keyboard_event/pubspec.yaml b/keyboard_event/pubspec.yaml
index e493587..cace506 100644
--- a/keyboard_event/pubspec.yaml
+++ b/keyboard_event/pubspec.yaml
@@ -14,7 +14,7 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: "<4.0.0"
 
 dependencies:
   flutter:
diff --git a/plugin_tutorial/pubspec.yaml b/plugin_tutorial/pubspec.yaml
index efa0abc..1c869ef 100644
--- a/plugin_tutorial/pubspec.yaml
+++ b/plugin_tutorial/pubspec.yaml
@@ -14,7 +14,7 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.2.0 <3.0.0"
+  sdk: "<4.0.0"
 
 dependencies:
   flutter:
diff --git a/pointer_demo/pubspec.yaml b/pointer_demo/pubspec.yaml
index 4849753..f21943a 100644
--- a/pointer_demo/pubspec.yaml
+++ b/pointer_demo/pubspec.yaml
@@ -14,7 +14,7 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: "<4.0.0"
 
 dependencies:
   flutter:
diff --git a/stocks/pubspec.yaml b/stocks/pubspec.yaml
index 5ab2183..97a2cef 100644
--- a/stocks/pubspec.yaml
+++ b/stocks/pubspec.yaml
@@ -3,7 +3,7 @@ description: A simple stocks application
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.0.0-dev.68.0 <3.0.0"
+  sdk: "<4.0.0"
 
 dependencies:
   flutter:
diff --git a/text_demo/pubspec.yaml b/text_demo/pubspec.yaml
index 192566c..08cf79f 100644
--- a/text_demo/pubspec.yaml
+++ b/text_demo/pubspec.yaml
@@ -14,7 +14,7 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: "<4.0.0"
 
 dependencies:
   flutter:
diff --git a/texture_tutorial/pubspec.yaml b/texture_tutorial/pubspec.yaml
index 4d8f17f..330825f 100644
--- a/texture_tutorial/pubspec.yaml
+++ b/texture_tutorial/pubspec.yaml
@@ -14,7 +14,7 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: "<4.0.0"
 
 dependencies:
   flutter:
diff --git a/xbox_controller/pubspec.yaml b/xbox_controller/pubspec.yaml
index 1336500..b689020 100644
--- a/xbox_controller/pubspec.yaml
+++ b/xbox_controller/pubspec.yaml
@@ -14,7 +14,7 @@ description: A new Flutter project.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.1.0 <3.0.0"
+  sdk: "<4.0.0"
 
 
 dependencies: