diff --git a/capnp/Cargo.toml b/capnp/Cargo.toml
index 5a551b1fe..db18ed0c5 100644
--- a/capnp/Cargo.toml
+++ b/capnp/Cargo.toml
@@ -8,6 +8,7 @@ description = "runtime library for Cap'n Proto data encoding"
 repository = "https://github.com/capnproto/capnproto-rust"
 documentation = "https://docs.capnproto-rust.org/capnp/"
 edition = "2021"
+rust-version = "1.65.0"
 
 readme = "README.md"