diff --git a/Cargo.toml b/Cargo.toml
index 7a722aad..6b7a22ce 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,7 @@
 [package]
 name = "rustls"
 version = "0.15.0"
+edition = "2018"
 authors = ["Joseph Birr-Pixton <jpixton@gmail.com>"]
 license = "Apache-2.0/ISC/MIT"
 readme = "README.md"