Errors occurred during installation while updating from OJS to OJS 3.0.2


I updated from 2.3.8 to and everything worked fine. Just some custom plugins needed adjustment.

Now, I wanted continue upgrading to 3.0.2. However, the upgrade script fails with
“Errors occurred during installation: Upgrade unsupported. See docs/UPGRADE-UNSUPPORTED for details.”
There is no detailed error message but only this.

I also downloaded a clean code base for OJS 3.0.2, copied the public directory, the submission directory, and the I tried upgrading again but ended with the same error.

Does anybody has an idea what the problem is?

This sounds as if OJS still thinks the database is structured as 2.3.x. Did you run the database upgrade after updating the code to 2.4.8-2? It would have involved the command line php tools/upgrade.php upgrade or using the Web installer with the “Upgrade” link? Did that process complete successfully?

Yes, I did. I think it was successful. There was no error message and the OJS was functional.

Is there an easy way to check whether the database structure is successfully converted to

I may have to mention that I have some additional tables used by custom plugins.

You can check the current status of the 2.x version as Site Administrator:
User Home → Site Administrator → System Information

Thanks, indeed, it stated that it is still version 2.3.8.