Since I got the device it would not connect to certain previously used WiFi networks. I reset modems/routers changed passwords, networks I could previously connect would not let me join while others worked perfectly. Saw a few threads about other people experience same thing.
Fi support would not acknowledge any know issues but the support they provided worked.
Settings... System... Reset options... Reset mobile network (do not need to reset sim). I even asked should I reset WiFi... She said no. After the reset I restarted my phone and I connected to the network I previously had issues with the new phone.
Hope it helps, I was worried I would have to wait for an update. I was blowing through cell data at work because it wouldn't connect to one of the main WiFi networks I used alot.
For Wi-Fi issues.