@MR.S Well , yes and no.

I tried several things, including downgrading to 5.13 (incl. uninstalling without removing pers. data and with removing pers. data and re-installing from scratch plus integrating plus backup. De-activated 2FA before in order not to mess up, but that did not really work.

Installed 5.14 again and all local devices were instantly up again. Remote site completely down. Decided to stop and revisit the whole thing over the weekend. During the next day

devices came up bit by bit with the last access point today at around 15H.

All set device names and IP allocations have gone and are lost, NAT rules no longer work (have not defined fixed IPs at the side of the devices connected, but used the "always allocate the same IP" function). Also, the whole thing is pretty unstable, I see Omads devices go and come. 
Not done yet, my next action will be a complete reboot of the remote site. 
Long story short: don't know whether the system just needed time to re-initialize, or if my activities (incl. downgrading/de-installing/installing) triggered anything.

Br's Thomas

  @Eg64 

yes I don't like it, especially since I ran early access which worked. so that they make changes to the release version compared to EA is not good. I expect and am prepared for problems when I install EA but not the release version.

what i did was i uninstalled the controller and didn't keep old data. downgraded and ran a restore from the backup I took just before I upgraded, then everything came back online. then I upgraded again to test but everything crashed again, downgraded and restored again and it was up again. then I did a lot of different things that I don't remember half of, among other things I changed all names of vpn tunnels to use underscores in and not hyphens, a while ago hyphens were forbidden to use. I also reset the ER8411 to deafult and readopted it before upgrading again, so when I upgraded for the 3rd time it worked.

  @Eg64 

Which router do you use on your remote sites? I have a linux controller with 3 remote sites, but I hardly know if I dare to upgrade it when the update comes.

  @MR.S 

ER8411 both sites

  Restarted second site - everything running smoothly since, no errors, all devices with their original assigned IPs etc.

To whom it may concern - quick update after migrating to 5.14.26.1:

Exactly the same behavior: no problems on the "controller site" while the remote site is more or less non-operational. Completely down first, then individual TP Link devices come back and drop off again. Some of the remote site clients seem to be connected to the internet, some seem to have lost connectivity. Will again need to restart the remote site completely.

Tend to agree with the opinion that it is an issue with the ER8411 router. Is the device which does not come back. 
 

BR's