diff --git a/pubspec.yaml b/pubspec.yaml
index 379eb9c5..8dd8edcd 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,6 +2,8 @@ name: angel_security
 version: 0.0.0-alpha
 description: Angel middleware designed to enhance application security.
 author: Tobe O <thosakwe@gmail.com>
+environment:
+  sdk: ">=1.19.0"
 homepage: https://github.com/angel-dart/security
 dependencies:
     angel_framework: ^1.0.0-dev