diff --git a/modules/angular2/pubspec.yaml b/modules/angular2/pubspec.yaml
index 5fe4e874c4..1bcf0c9782 100644
--- a/modules/angular2/pubspec.yaml
+++ b/modules/angular2/pubspec.yaml
@@ -19,7 +19,7 @@ dependencies:
   source_span: '^1.0.0'
   stack_trace: '^1.1.1'
   quiver: '^0.21.4'
-  observe: '0.13.1'
+  observe: '^0.13.1'
 dev_dependencies:
   guinness: '^0.1.17'
 transformers: