diff --git a/README.md b/README.md
index 05413c5..9a6651f 100644
--- a/README.md
+++ b/README.md
@@ -65,7 +65,7 @@ Please see [the benchmark](benches/bench.rs) for a bigger (and useful) example.
 
 ### Required Rust version
 
-`1.38 stable`
+`1.40 stable`
 
 ## Features