diff --git a/serde_test/Cargo.toml b/serde_test/Cargo.toml
index 848e7d49c..de5ec2c1f 100644
--- a/serde_test/Cargo.toml
+++ b/serde_test/Cargo.toml
@@ -2,7 +2,7 @@
 name = "serde_test"
 version = "1.0.136" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
-rust-version = "1.15"
+rust-version = "1.13"
 license = "MIT OR Apache-2.0"
 description = "Token De/Serializer for testing De/Serialize implementations"
 homepage = "https://serde.rs"