If you call tech support they might be able to get you on a list to force an update. Its possible that there wasn't enough of a difference between .4.1 and.4.3 to cause Rogers to commence another round of system wide updates. Just guessing.
You don't need .4.3 to run in Bridge mode however. Since Bridge mode is user selectable you can choose to run in that mode with your current firmware and do so at any time.