diff --git a/Cargo.toml b/Cargo.toml
index faf86b7..2f9d744 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,4 +17,4 @@ std = []
 
 [dev-dependencies]
 proptest = "1.0.0"
-proptest-derive = "0.3.0"
+proptest-derive = "0.4.0"