It is a bit try and error
But clearly:
Switching from 7.x.x to another 7.x.x based rom should work
Switching from 6.x.x to another 6.x.x based rom should work as well.
Switching between differend android main versions (6 to 7 or vice versa) will bring troubles anytime.
Always make a full twrp backup for all partitions. If something is not working: reload your saved Backup