05-03-2013 06:48 PM
Unless someone happens to keep track, there isn't a really good source of an answer to that question. It all starts with the official download portal:
Since they are responsible for all support, release of the OS is controlled by each carrier to their end users. So, to answer the question regarding your specific carrier is relatively easy...you navigate the portal to your carrier and compare the various OS levels that they presently support for your specific model number BB.
But, some carriers are slower than others to release newer OS's...and therefore "the newest" might not actually be released by your carrier yet. Hence, to truly find the overall "newest", you must dig through the portal to find all carriers that support your specific model number BB...and then compare the OS levels that each supports.
You are not restricted to using your carriers OS levels...with the proper tricks, you can use any OS package from any carrier, as long as it's for your exact same model number BB.