1. ALWAYS create a backup of your configuration and data before a firmware upgrade.
2. After upgrading to 1.0.20.x, if you downgrade to 1.0.19.x and issues are encountered after downgrading, factory reset the UCM and restore the backup.
3. For UCM6xxx on 1.0.19.x, please upgrade to 1.0.20.x directly.
4. For UCM6xxx on firmware earlier than 1.0.20.x, please upgrade to 188.8.131.52 first, then upgrade to 1.0.20.x. To upgrade to 184.108.40.206, please check 220.127.116.11 release note “Important Upgrading Note” section and follow the instructions.
5. It is recommended to upgrade UCM to latest firmware for product lifespan and security improvements.