Adapt ChangeLog
diff --git a/ChangeLog b/ChangeLog
index 7ef0342..3a73544 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -32,6 +32,8 @@
      in the same way as on the server side.
    * Change the dtls_client and dtls_server samples to work by default over
      IPv6 and optionally by a build option over IPv4.
+   * Improve documentation of mbedtls_ssl_get_verify_result().
+     Fixes #517 reported by github-monoculture.
 
 = mbed TLS 2.1.15 branch released 2018-08-31