diff --git a/src/doc/src/reference/registries.md b/src/doc/src/reference/registries.md
index 0289524b3d7..212fbf566db 100644
--- a/src/doc/src/reference/registries.md
+++ b/src/doc/src/reference/registries.md
@@ -29,6 +29,7 @@ in `Cargo.toml`:
 [package]
 name = "my-project"
 version = "0.1.0"
+edition = "2021"
 
 [dependencies]
 other-crate = { version = "1.0", registry = "my-registry" }