diff --git a/bower.json b/bower.json
index f9f4502..6667879 100644
--- a/bower.json
+++ b/bower.json
@@ -14,8 +14,8 @@
     "Backbone", "undo"
   ],
   "dependencies" :{
-    "underscore": "~1.4.4",
-    "backbone": "~1.0.0"
+    "underscore": "1.4.4 - 1.8.3",
+    "backbone": "1.0.0 - 1.2.1"
   },
   "ignore": [
     "Tests",
diff --git a/package.json b/package.json
index 156290f..f6dd065 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
     "url": "https://github.com/osartun/Backbone.Undo.js/issues"
   },
   "dependencies": {
-    "backbone": "~1.0.0",
-    "underscore": "~1.4.4"
+    "backbone": "1.0.0 - 1.2.1",
+    "underscore": "1.4.4 - 1.8.3"
   }
 }