Lots of posts today about various GSM firmware versions and the latest v6.xxx one.
Confusing though I must say as they all seem to have their respective merits and chipset support.!
Given I believe you've had a few hardware moudles of the GSM card (different chipsets?) are you saying there is a matrix of what firmware works with which hardware or does v6.xxx work with all models (past and present) of teh UCM/GSM card?
The later UCM/GSM firmware always supports all the previous hardware GSM chipsets. What is mentioned in the firmware history is the new modules supported so there should be no concern about upgrading firmware.
There are a lot of changes in the GSM module industry with some becoming obsolete and new ones becoming available, and manufacturers being taken over by others and line consolidation