Latest T48G Skype for Business Firmware

I have been given a demo T48G to review. I have been trying to upgrade it to the latest Skype for Business Firmware.

However there appears to be a number of different versions on a number of your web pages.

The phone came with 35.8.0.21
The following URL's have different latest versions.

Phone has 35.8.0.21

http://www.yealink.co.uk/Firmware
Has firmware at 35.80.23.1

http://support.yealink.com/documentFront...cumentId=2
Has latest Firmware as 35.80.0.95

http://www.yealink.com/solution_info.asp...ateId=1328
Has latest Firmware as 35.7.0.50

Can you please confirm what the latest firmware is for the T48G for Skype for Business and provide a valid link to it.

Regards