@FS72 I just did a ProcessWire 2.2 to 3.0.244 upgrade. You are right that you have to use 2.7 as the "intermediate" version when upgrading to a 3.x version (per the README). This is because 2.7.2 was the version that was prepared for the major 3.x changes. So you'll want to upgrade to 2.7.2 first. Once upgraded to 2.7, then you can upgrade to any 3.x version. In my case, some of the user accounts wouldn't transition over because 2.2 was from 13 years ago and used a different password system, so that's something to keep in mind. I ended up creating an admin account and then installed the profile exporter module, then did a fresh install with the newly created profile. That way I was starting with a fresh install, despite the site being from 2012.