diff --git a/pubspec.yaml b/pubspec.yaml
index ee1f309..f9c3b67 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -4,6 +4,9 @@ version: 1.3.0
 author: Posse Productions LLC <apps@goposse.com>
 homepage: https://github.com/goposse/fluro
 
+environment:
+  sdk: ">=1.23.0 <2.0.0"
+
 dependencies:
   flutter:
     sdk: flutter