diff --git a/rustbook-en/book.toml b/rustbook-en/book.toml
index b73ff03b7..800adcf0f 100644
--- a/rustbook-en/book.toml
+++ b/rustbook-en/book.toml
@@ -15,3 +15,6 @@ git-repository-url = "https://github.com/rust-lang/book"
 
 [preprocessor.trpl-listing]
 output-mode = "default"
+
+[rust]
+edition = "2021"