Check settings about wifi activity when screen locked first. Then check /config/WiFi/ do you have mac.txt file there. If not - you should create it and put your device mac address there. Let me know. I'll provide detailed instruction.
I checked that the mac.txt existed and does have my MAC address correctly stored in it.
However, I am staying at a guesthouse at the moment and the wifi login needs to be entered through a 10.0.0.254 URL using a personal username and password.
The main point being is that under the older o/s I only needed to re-enter whenever I powered-off the device or took it out of wifi range.
With this new o/s, it requires re-entering the login details everytime I use the device (after sleep).....something changed?!?