Partial database migration to a fresh install - tables required?

[Pepe LeFrits]

I've upgraded my copy of MyBB to 1.8 but to say I am having problems would be an understatement. I've installed a fresh copy of 1.8 and am looking to migrate part of my database into it.

Question - is this possible, and if so, what is the bare minimum I need, tables-wise, to move across? 

forumpermissions
forums
posts
threads
usergroups
users
?

Thanks.

---

I used those tables and it seems to work, mostly. Have had to tweak the datacache table a little but no major issues.