importing user accounts, data and pics into elgg 4.0

I have been working with tech support to upgrade from 2.3.17 -> 3.3.21 -> 4.0 with no success at all. I'm thinking to do a full backup of 2.3.17 erase the existing app, install a fresh 4.0 and then import all user data from backup of 2.3.17 is this possible and if so is there any documentation that helps with this thank you.