Note in the changelog that this fixes an interoperability issue.

Fixes #1339
diff --git a/ChangeLog b/ChangeLog
index 4189089..01e2a73 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,7 +5,9 @@
 Features
    * Extend PKCS#8 interface by introducing support for the entire SHA
      algorithms family when encrypting private keys using PKCS#5 v2.0.
-     Submitted by Antonio Quartulli, OpenVPN Inc.
+     This allows reading encrypted PEM files produced by software that
+     uses PBKDF2-SHA2, such as OpenSSL 1.1. Submitted by Antonio Quartulli,
+     OpenVPN Inc. Fixes #1339
 
 = mbed TLS 2.7.0 branch released 2018-02-03