I just completed an upgrade from 6.5.3 to 7.10. Everything appears to be good with the exception of all my custom fields not saving to the DB. I can edit but when I save CRM return me to the Display View and the custom fields have been blanked.
Did you do a Quick Repair and Rebuild? And make sure you scroll to the bottom and press to “sync vardefs” if there is a button there to do it.