And another post on WiFi... The ongoing battle to stop our iPhones losing connection when roaming between Unifi APs.
The latest change seems to have worked. I really hope I am not coming back next week and updating this post to say otherwise. But really, it has been several days now, and no problem.
The change was to put the APs (Unifi AC Pro and AC Pro LR) on firmware 18.104.22.16869.
I had to change the controller to unifi5 to get this latest version
deb http://www.ubnt.com/downloads/unifi/debian unifi5 ubiquiti
The iPhone is not off the hook entirely though - as even when it did not get DHCP and knew the WiFi was therefore not working, with a self allocated 169.254 address, it would still try and use the WiFi and not the 3G even with WiFi assist. So it was being dumb. But not as bad as I thought...
The other change in the latest firmware and controller that I have noticed is 14 more 5GHz channels, so 18 rather than just the 4 we had before. This will help avoid interference from other APs.
So, fingers crossed. This may be the answer.
P.S. One case of losing DHCP since...
P.P.S. Working quite well but has now failed a few times, so IS NOT A FINAL SOLUTION YET!