diff --git a/README.md b/README.md
index d8aea219d..9cc30da7f 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,8 @@ $ cargo +beta build
 #### `Cargo.toml`
 
 ```toml
+edition = "2018"
+
 [dependencies]
 tonic = "*"
 bytes = "0.4"