diff --git a/Cargo.toml b/Cargo.toml
index a12117b..15604cf 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@ repository = "https://github.com/sozysozbot/cetkaik_full_state_transition"
 cetkaik_calculate_hand = "0.3.1"
 cetkaik_core = "0.3.8"
 cetkaik_yhuap_move_candidates = "0.2.8"
-readonly = "0.2.0"
+readonly = "0.2.1"
 maplit = "1.0.2"
 enum_primitive = "0.1.1"
 num = "0.4.0"