I have the same problem. I tried to view my domoticz pages but could not get past the pop-up that told me to ugrade to 2020-1.
No notes on having to install a new OS first. Now my system doesn't work. No back-up made.
So pls advice with detailed instructions on either:
1 - revert to the previous version of Domoticz
2 - how to upgrade to the lastest Debian/Raspian version in order to get Domoticz working
I still have acces to my RP3+ through Putty and/or Winscp.
I hope anyone can help/
For future releases pls add the option not to install the update (was not possible this time) or warn the people that a needs an updated version of the OS to work. I had a perfect working system before this happened.
----------------------------------------------------------------------------------------------------
Decided to go ahead and try to upgrade to Buster on my Pi3+
Followed the outlines on the following site:
https://pimylifeup.com/upgrade-raspbian ... an-buster/
This indeed upgraded Stretch to Buster.
But Domoticz 2020.1 was still unreachable, but running updaterelease in the domoticz directory (through the terminal server) fixed that problem.
Happy times !!!!