diff --git a/zcash_proofs/Cargo.toml b/zcash_proofs/Cargo.toml
index b7fa659..766db63 100644
--- a/zcash_proofs/Cargo.toml
+++ b/zcash_proofs/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.0.0"
 authors = [
     "Jack Grigg <jack@z.cash>",
 ]
+edition = "2018"
 
 [dependencies]
 bellman = { path = "../bellman" }