diff --git a/CHANGELOG.md b/CHANGELOG.md
index b3de9988b..ffe049920 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,15 +7,16 @@ A breaking change will get clearly marked in this log.
 ## Unreleased
 
 
-## [v12.0.0](https://github.com/stellar/js-stellar-sdk/compare/v11.3.0...v12.0.0)
+## [v12.0.0-rc.1](https://github.com/stellar/js-stellar-sdk/compare/v11.3.0...v12.0.0-rc.1)
 
 ### Breaking Changes
-* **This update supports Protocol 21** ([#949](https://github.com/stellar/js-stellar-sdk/pull/949)).
+* **This update supports Protocol 21**. It is an additive change to the protocol so there are no true backwards incompatibilities, but your software may break if you encounter new unexpected fields from this Protocol ([#949](https://github.com/stellar/js-stellar-sdk/pull/949)).
 
 ### Fixed
 * Each item in the `GetEventsResponse.events` list will now have a `txHash` item corresponding to the transaction hash that triggered a particular event ([#939](https://github.com/stellar/js-stellar-sdk/pull/939)).
 * `ContractClient` now properly handles methods that take no arguments by making `MethodOptions` the only parameter, bringing it inline with the types generated by Soroban CLI's `soroban contract bindings typescript` ([#940](https://github.com/stellar/js-stellar-sdk/pull/940)).
 * `ContractClient` now allows `publicKey` to be undefined ([#941](https://github.com/stellar/js-stellar-sdk/pull/941)).
+* `SentTransaction` will only pass `allowHttp` if (and only if) its corresponding `AssembledTransaction#options` config allowed it ([#952](https://github.com/stellar/js-stellar-sdk/pull/952)).
 
 
 ## [v11.3.0](https://github.com/stellar/js-stellar-sdk/compare/v11.2.2...v11.3.0)