Installing older version

[Alain]

I have a rather extensive Domoticz system with multiple remote servers running. On one of the servers I run a Modbus plugin to control my heat pumps. That works very well. It is the only process running on that remote server. It has Domoticz 2021 build 13502 on it.

I have recently set up another remote server with the Modbus plugin to control a new set of heat pumps. I am continually getting errors because values are not being read. After a lot of trying and searching for answers, it has come to my attention that this problem has occurred since Domoticz 2022 version.

To solve the problem I'm having, I would like to downgrade to Domoticz 2021 build 13502 on this new remote server. Where can I find the correct files for this? Or can I copy certain files or folders from the "good" system? That would be the easiest solution. I'm running Ubuntu 20.04 on both machines.

[kiddigital]

The main part of Domoticz is a single executable so you can copy it from your working system.

But keep in mind that you need to have the right (same) environment as the original system to run it. You can’t copy the Linux executable onto a Windows system or ARM/Pi system. And vice versa.

Check the list of changes between the working and current version to see if you can identify changes that might cause your problem. You would expect the newer versions to do better, not worse.

[Alain]

The main part of Domoticz is a single executable so you can copy it from your working system.

But keep in mind that you need to have the right (same) environment as the original system to run it. You can’t copy the Linux executable onto a Windows system or ARM/Pi system. And vice versa.

Check the list of changes between the working and current version to see if you can identify changes that might cause your problem. You would expect the newer versions to do better, not worse.

Where would I find the correct file(s)? I have copied several different files from different locations, but none of them have changed the system to 2021.1.

[Alain]

I finally found the executable file. Replaced it in the /home/alain/domoticz directory and rebooted the system.

No errors but in the webbrowser it showed offline. I checked the status in a terminal window with sudo systemctl status domoticz.service and it says status exited.

I checked the architecture on both machines with uname -a and they display exactly the same, x86_64.

I wonder what is causing domoticz to exit as soon as it starts.

[kiddigital]

It exits directly probably because the database version is newer than expected.

When you installed the new version, it probably upgraded your database to a higher version.

You need to downgrade the database (undo the changes and version) or better is to go back to the database backup from before the upgrade.

Alternative is to start over with a new/empty database which Domoticz will create automatically if it can not find an existing database (look for the ‘domoticz.db’ file).

[Alain]

How can I downgrade the database? Replacing the database would be a lot of work as I have quite a few modbus registers programmed and implemented in scripts.

[kiddigital]

How can I downgrade the database? Replacing the database would be a lot of work as I have quite a few modbus registers programmed and implemented in scripts.

The version of the db can be found in the Preferences table, see field DB_Version.

You can have a look at the code in main/SQLHelper.cpp to see what changes between versions.

You need to go back to the DB_Version that is supported by the Domoticz version you are running. I think the logging of Domoticz shows (maybe you need to enable Debug logging, not sure) what version is expected when exiting because it found a higher version.

Also check the Wiki here.

If your version and configuration are not using/depending on any of the database changes, you could try to run the older version while keeping the DB changes (just lower the DB_Version). Otherwise you might have to revert some of the changes.

Warning: This is going into dangerous territory! Messing with the database might cause serious issues now and/or in the future when upgrading if/when you are modifying the wrong things. Make backups!

[Alain]

Thanks for the help. I downloaded sqlite3 and copied the domoticz.db file to a network directory. The opened it with sqlite3 and changed the version number of the database under preferences (from 155 to 149). I deleted the domoticz.db file on the machine and replaced it with the modified version. Everything now works as it should and I am on version 2021.1 (build13502).