diff --git a/pubspec.yaml b/pubspec.yaml
index 0c5d78e7..6092b2e5 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -4,7 +4,7 @@ description: A web-based scriptable cadnano (see https://cadnano.org/ for origin
 #author: David Doty <doty@ucdavis.edu>
 
 environment:
-  sdk: '>=3.0.0 <4.0.0'
+  sdk: '>=3.5.0 <4.0.0'
 
 dependencies:
   analyzer: ^6.8.0