I have the official 7.2.0RC3 installed (is there a official and supported thread for that?).
Can anyone confirm this:
1. Let mobile phone WiFi connect to any network.
2. Turn off WiFi on Mobile Phone.
3. Turn off WiFi on Router.
4. Turn on WiFi on Mobile Phone (no network --> no connection, of course).
5. Turn on WiFi on Router.
6. Phone won't connect to any network and will time out waiting for an IP address from the router, but you can work with the phone - without WiFi of course.
This is how you can avoid the issue, after it happend:
Settings --> Network. WiFi is still waiting for IP-Adress. Turn off WiFi, wait a moment and turn it on again. WiFi will now connect to the network again.
This happened at 7.1.0 and 7.2rc1+2, too.