I installed the upgrade on my test environment and the problem is with the wifi MAC Address random generation. I use a RTL 8192 wifi dongle and the standard driver generate a random MAC Address every time I power on the PC and, every time, I must digit the WIFI password.
I try the Phil solution but, as I wrote in previous post, it doesn't work, at least for me.
To solve the problem I use, from more than 1 year, the 8192cu-dkms package in AUR, its a lot better, faster, stable and no random MAC address problem, but time to time, it become unusable. It happen with this upgrade too, so, I'll wait to read that somebody has solved the problem, before to upgrade.
This is the only problem I was able to verify.
I find the solution looking around in the forum, thanks' to Knoife: downgrading wpa_supplicant to the 2.5-3 version all work correctly. I'm using my test environment and the 8192 dongle.
Kernel 4.7.7-1, Openrc, Plasma.