When I am coping database files to PC where restoration needs to be done, should I overwrite "Duplicati-server.sqlite" that is created after Duplicati installation of keep it?

I want to restore my backup on a new PC. I have a copy of whole database folder from old PC. On the new PC I installed Duplicati and I see the “Duplicati-server.sqlite” file in database folder. Should I overwrite “Duplicati-server.sqlite” from old PC or keep new one?

It will make no difference to the restore you are trying to perform. What would be more ideal is a copy of the database and the job itself so that you can perform a “Restore from configuration”. If you don’t have the job JSON file you’ll need to perform your restore from the CLI and specify the DB.

I have configuration file too and I am planning to use it too. But I am interesting about “Duplicati-server.sqlite”, what that file is doing and should I overwrite it with the old one or keep the new one?

The duplicati-server.sqlite file essentially holds the configuration of each backup, like what you see in exported configurations.

As such, copying all databases, including the duplicati-server.sqlite, will essentially port your installation to the new system with all the same configurations.