If you still are relying upon a PS/2 mouse, it really is time to think about upgrading to a USB mouse, but keep reading as there are some changes with Linux 4.5.
The PS/2 mouse change is that its module has been reworked in order to "limit number of protocols we try on pass-through ports to speed up their detection time." Not too exciting but it's an improvement nevertheless if stuck using this technology dating back to the late 80's.
As a follow-up to last week's X.Org Might Lose Its Domain Name, where it looked like the X.Org Foundation would lose their single-letter domain unless getting very lucky, they managed to get their domain renewed today. The X.Org Foundation has yet to issue a statement, but perhaps thanks to all the public pressure the past few days had a helping hand in getting the domain situation sorted out in a timely manner.