Which is the latest version of the UCM/GSM module? i.e. 2 or 3?
What are the differences between the two?
UCM/GSM3 is a replacement for UCM/GSM2. The distinction is due to a change in the GSM component. Other than that the performance is the same
Will UCM/GSM1 work with Ultra 6.xxx firmware
and can it be flashed to the latest firmware?
The UCM/GSm1 with firmware version 4 will not be able to flash to the latest firmware
If your UCM/GSM is firmware version 5 and above then it can be flash to thelatest firmware