diff --git a/Cargo.toml b/Cargo.toml
index 5b7d9cd8..31447e40 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,7 @@ iron-handlers = ["iron"]
 expose-test-schema = []
 
 [dependencies]
-rustc-serialize = "0.3.19"
+rustc-serialize = "^0.3.19"
 iron = { version = "^0.4.0", optional = true }
 
 [dev-dependencies]