diff --git a/pubspec.yaml b/pubspec.yaml
index f531f46..b2c9358 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,4 +1,5 @@
 name: oauth2
+version: 0.9.0
 author: "Dart Team <misc@dartlang.org>"
 homepage: http://www.dartlang.org
 description: >
@@ -6,6 +7,8 @@
   behalf of a user, and making authorized HTTP requests with the user's
   OAuth2 credentials.
 dependencies:
-  http: any
+  http: ">=0.9.0 <0.10.0"
 dev_dependencies:
-  unittest: any
+  unittest: ">=0.9.0 <0.10.0"
+environment:
+  sdk: ">=1.0.0 <2.0.0"