diff --git a/programs/zk-token-proof/Cargo.toml b/programs/zk-token-proof/Cargo.toml
index de7d94d664..5a2fb514fc 100644
--- a/programs/zk-token-proof/Cargo.toml
+++ b/programs/zk-token-proof/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["Solana Maintainers <maintainers@solana.foundation>"]
 repository = "https://github.com/solana-labs/solana-program-library"
 version = "0.1.0"
 license = "Apache-2.0"
-edition = "2018"
+edition = "2021"
 publish = false
 
 [dependencies]