diff --git a/Cargo.toml b/Cargo.toml
index 5eebbcc..1550a42 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ keywords = ["email", "smtp", "parser", "codec"]
 version = "0.1.0"
 repository = "https://github.com/InstantDomain/instant-smtp"
 license = "MIT OR Apache-2.0"
-edition = "2018"
+edition = "2021"
 
 [features]
 default = []