diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 2d9aab1..4b40973 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -3,7 +3,7 @@ description: SpinBox for Flutter example app.
 publish_to: 'none'
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: '<4.0.0'
 
 dependencies:
   flutter_spinbox: