diff --git a/Cargo.toml b/Cargo.toml
index 0248d63242b98e3d6be3d4343d64eb6adf87b356..f32b593bd1b50de04db616b3f2c5057863479f39 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,6 +13,7 @@ maplit = "1.0.2"
 derive_more = "0.99.2"
 
 # runtime
+serde = { version = "1.0.112", features = ["derive"] }
 getrandom = "0.1.14" # tiny crate. used to guess controller-id
 take_mut = "0.2.2"
 indexmap = "1.3.0" # hashsets/hashmaps with efficient arbitrary element removal
@@ -24,7 +25,7 @@ mio = "0.6.21" # migrate to mio v0.7.0 when it stabilizes
 mio-extras = "2.0.6"
 
 # protocol
-id-arena = "2.2.1"
+# id-arena = "2.2.1"
 backtrace = "0.3"
 
 [dev-dependencies]