diff --git a/pubspec.yaml b/pubspec.yaml
index a0dcf175..a2bddae2 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,7 @@
 author: "Tobe O <thosakwe@gmail.com>"
 description: "Angel CORS middleware."
+environment:
+  sdk: ">=1.19.0"
 homepage: "https://github.com/angel-dart/cors.git"
 name: "angel_cors"
 version: "1.0.0-dev"