I wouldn't roll back if you have a newer build, and in some cases, the television will not allow you to roll back.

I don't know what happened with the firmware. Unfortunately, I can only speak on U.S. models and service. The best I can suggest is to call the Samsung customer service center in your region to inquire further. If the TV is working fine with the firmware, then there's no need to upgrade (and especially, in most cases, downgrade).