diff --git a/Cargo.toml b/Cargo.toml
index 3a68f37..9dc7128 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -12,6 +12,7 @@ version = "0.22.0"
 edition = "2018"
 readme = "README.md"
 include = ["examples/**/*", "src/**/*", "LICENSE", "README.md", "CHANGELOG.md"]
+rust-version = "1.63"
 
 [features]
 default = ["handshake"]