Okay, I have 7.0.2 instance. What is well known path? I already tried
7.0.2 → 7.0.15 fails on duplicate column
7.0.2 → 8.2.11 fails with message about skipping major versions
7.0.2 → 10.2.1 fails with message about skipping major versions
@boldlookup: Just for my personal curiosity: Have you been using oc7 since then, or is it a zombie installation to be revitalized now? What is or was the reason to keep it without any upgraded all the time?
Depending of your content and the count of users it might be simpler to start over directly with a new install of the latest version.