diff --git a/CHANGES.md b/CHANGES.md
index bc89f24fb0..84c8d433a9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -70,6 +70,8 @@ To be released.
  -  The difficulty was changed from representing the number of leading zeros of
     target number to representing a divisor to obtain the target number.
     [[#213]]
+ -  Removed unnecessary reader lock on `BlockChain<T>.StageTrasactions()`. [[#217]]
+ -  Improve concurrency of `BlockChain<T>.GetState()`. [[#217]]
 
 [#185]: https://github.com/planetarium/libplanet/pull/185
 [#187]: https://github.com/planetarium/libplanet/issues/187
@@ -81,6 +83,7 @@ To be released.
 [#210]: https://github.com/planetarium/libplanet/pull/210
 [#213]: https://github.com/planetarium/libplanet/pull/213
 [#215]: https://github.com/planetarium/libplanet/pull/215
+[#217]: https://github.com/planetarium/libplanet/pull/217
 [Ethereum Homestead algorithm]: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-2.md