diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs
index d8c2e0b2a3b..ea8070534eb 100644
--- a/library/core/src/convert/mod.rs
+++ b/library/core/src/convert/mod.rs
@@ -623,7 +623,7 @@ impl AsRef<str> for str {
     }
 }
 
-#[stable(feature = "as_mut_str_for_str", since = "1.50.0")]
+#[stable(feature = "as_mut_str_for_str", since = "1.51.0")]
 impl AsMut<str> for str {
     #[inline]
     fn as_mut(&mut self) -> &mut str {