diff --git a/elm-package.json b/elm-package.json
index 4b69e1c..d8f23cc 100644
--- a/elm-package.json
+++ b/elm-package.json
@@ -9,6 +9,6 @@
     "exposed-modules": [],
     "native-modules": true,
     "dependencies": {
-        "elm-lang/core": "1.0.0"
+        "elm-lang/core": "1.0.0 <= v < 2.0.0"
     }
 }
\ No newline at end of file