1. Backup your data including configuration before firmware upgrade is recommended.
2. For UCM6510 on 1.0.14.x, please upgrade to 188.8.131.52 directly.
3. For UCM6510 on firmware lower than 1.0.14.x, please follow upgrading instructions in UCM6510 release note to upgrade to 184.108.40.206 first, then upgrade to 220.127.116.11.
4. After upgrading successfully, please clear cache or refresh your UCM web UI in your web browser before configuring UCM again.
5. This firmware has fixed a backup issue on firmware 18.104.22.168 which causes backup failure when CDR has lots of data. If your UCM is on 22.214.171.124 and cannot create backup file, please use a backup file from 1.0.14.x or contact Grandstream tech support for assistance.