Transferring 3.8.x users only to 4.1

[Lynne]

I would set up a test site, try installing 4.1 and then, since you only want the users, try using Impex to only import the users. See if that works.

Optionally, use Calorie's database compare utility (do a search - it's in the 3.8 area) and see what extra tables/fields are in your database and do whatever with that info - delete them, keep them, you decide. Then do an upgrade.