1. ALWAYS create a backup of your configuration and data before a firmware upgrade.
2. If downgrading from firmware version 188.8.131.52+ to 184.108.40.206 or lower, users must factory reset the UCM and restore a backup created on the corresponding lower version to minimize potential issues from the downgrade. Please note that restoring a backup created on 220.127.116.11+ to a UCM on 18.104.22.168 or lower may cause abnormal system behavior.
3. For UCM6xxx on firmware earlier than 1.0.20.x, please upgrade to 22.214.171.124 first, then upgrade to 1.0.20.x. To upgrade to 126.96.36.199, please check 188.8.131.52 release note “Important Upgrading Note” section and follow the instructions.
4. It is recommended to upgrade UCM to latest firmware for product lifespan and security improvements.