Out of curiosity, did you maybe do an upgrade in more than one step? Or maybe do the upgrade, and then for some reason reload the original 2.4.8.4 database and upgrade again?
I ask because your error happened to me this morning, when I was upgrading a journal. I had originally done a 2.4.7 to 3.1.2 upgrade, by first upgrading to 2.4.8 and then going to 3.1.2. Absolutely no problems. Then this morning I was going to do it for real, and I started with a fresh 2.4.7 SQL dump that I loaded into my db again. The SQL dump contained DROP TABLE statements for the existing 2.4.7 database tables, but not the 3.1.2 tables, so during the upgrade process I ended up trying to insert records into the review_round_files table, but since there were already records from the previous upgrade I received the key error. Starting completely fresh with an empty database, no problem.
Hey @jnugent , time ago i migrated it from 2.4.7 to 2.4.8.4. Think the solution would be to clean up the table review_round_files before upgrade ti 3.1.2 ?
That table may be fine, but maybe make sure that there aren’t any “migration” tables lying around. OJS does create some temporary tables when it performs upgrades, and maybe one of those is still being used and/or added to with new records.