diff --git a/ChangeLog b/ChangeLog
index ee85a9b..fcf1019 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,9 @@
    * Allow comments in test data files.
 
 Bugfix
+   * Fix wrong implementation of truncated HMAC extension leading to
+     compatibility problems with peers not running Mbed TLS. Found by
+     Andreas Walz.
    * Fix ssl_parse_record_header() to silently discard invalid DTLS records
      as recommended in RFC 6347 Section 4.1.2.7.
    * Fix memory leak in mbedtls_ssl_set_hostname() when called multiple times.