diff --git a/src/lib.rs b/src/lib.rs
index 4baa4c2..00d6126 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,7 +11,6 @@
 
 #![no_std]
 #![cfg_attr(feature = "nightly", feature(test))]
-#![cfg_attr(feature = "nightly", feature(external_doc))]
 #![cfg_attr(feature = "nightly", feature(doc_cfg))]
 #![cfg_attr(feature = "simd_backend", feature(stdsimd))]