In case anyone else is looking for this, I contacted a seller who has told me that Fluke did the hardware / software mod in 2013.
Although I have found a few reviews still complaining about short battery life that were posted after 2017 so not sure if they were complaining about new gear or an old unit they bought.
I pulled the pin and bought one as the dedicated display seems more convenient than the Keysight bluetooth app/dongle that always seems to get interrupted by a phone call just as I'm getting the reading I want.
Cheers .