Upgraded yesterday, machine is still multiregion, can see no visible changes to menus. The instructions explain how to upgrade and check the new firmware number to confirm it has been upgraded.
Dont know what it changes but a couple of discs i had that had strange properties e.g. certain menu buttons not always responding work perfectly now.
Hope this is of some help.
PS If you go in to get the disc i was told to take my receipt with me?.
Be warned.