Firmware branch
The firmware branch is the second number in firmware name.
Eg: FMXX.Ver.AA.BB.CC, BB is the branch of the firmware version.
When updating a device,
If the old firmware version and the new one have the same branch then, configuration will not be reset.
For example: Updating from FM63.Ver.01.00.06 to FM63.Ver.01.00.17 will not be reset configuration.
If the branch of the old firmware version and the new one are different then, configuration will be probably reset.
For example: Updating from FM63.Ver.00.02.117 to FM63.Ver.01.00.17 will be reset configuration.