diff --git a/polkadot/parachain/test-parachains/undying/Cargo.toml b/polkadot/parachain/test-parachains/undying/Cargo.toml
index 40eb21d5dbfa95111ef9450b46b7f09beac5103d..9c9825fe9ff19b3b10b796f974a59897f536c6b9 100644
--- a/polkadot/parachain/test-parachains/undying/Cargo.toml
+++ b/polkadot/parachain/test-parachains/undying/Cargo.toml
@@ -8,7 +8,7 @@ build = "build.rs"
 
 [dependencies]
 parachain = { package = "polkadot-parachain", path = "../../", default-features = false, features = [ "wasm-api" ] }
-parity-scale-codec = { version = "2.3.1", default-features = false, features = ["derive"] }
+parity-scale-codec = { version = "3.0.0", default-features = false, features = ["derive"] }
 sp-std = { git = "https://github.com/paritytech/substrate", branch = "master", default-features = false }
 tiny-keccak = { version = "2.0.2", features = ["keccak"] }
 dlmalloc = { version = "0.2.3", features = [ "global" ] }
diff --git a/polkadot/parachain/test-parachains/undying/collator/Cargo.toml b/polkadot/parachain/test-parachains/undying/collator/Cargo.toml
index 3e02a76e66133c85e6319a047ad257c3a793eb60..f52d9736e9bbdb8e9917f0362d2903291ee442c8 100644
--- a/polkadot/parachain/test-parachains/undying/collator/Cargo.toml
+++ b/polkadot/parachain/test-parachains/undying/collator/Cargo.toml
@@ -14,7 +14,7 @@ name = "undying_collator_puppet_worker"
 path = "bin/puppet_worker.rs"
 
 [dependencies]
-parity-scale-codec = { version = "2.3.1", default-features = false, features = ["derive"] }
+parity-scale-codec = { version = "3.0.0", default-features = false, features = ["derive"] }
 clap = { version = "3.0", features = ["derive"] }
 futures = "0.3.19"
 futures-timer = "3.0.2"