diff --git a/pubspec.yaml b/pubspec.yaml
index 1ca8146..b8ece24 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -9,7 +9,7 @@ repository: https://github.com/Flagsmith/flagsmith-flutter-core
 issue_tracker: https://github.com/Flagsmith/flagsmith-flutter-core/issues
 
 environment:
-  sdk: ^3.0.0
+  sdk: ">=3.0.0 <4.0.0"
 
 dependencies:
   crypto: ^3.0.1