diff --git a/spec/_attachments/interface-spec-changelog.md b/spec/_attachments/interface-spec-changelog.md
index 46a94a5c3..a13e2f765 100644
--- a/spec/_attachments/interface-spec-changelog.md
+++ b/spec/_attachments/interface-spec-changelog.md
@@ -4,6 +4,7 @@
 * Canister cycle balance cannot decrease below the freezing limit after executing `install_code` on the management canister.
 * System API calls `ic0.msg_caller_size` and `ic0.msg_caller_copy` can be called in all contexts except for (start) function.
 * Added note on confidentiality of values in the certified state tree.
+* Update algorithm computing the request and response hash in the HTTP Gateway including clarification of when the HTTP Gateway can allow for arbitrary certification version in the canister's response.
 
 ### 0.20.0 (2023-07-11) {#0_20_0}
 * IC Bitcoin API, ECDSA API, canister HTTPS outcalls API, and 128-bit cycles System API are considered stable.