upgrading to threads is no big deal.As long as you follow the manual
It will leave the classic board intact and functional.
In fact it does not alter the old board at all. It just reads the data and imports it to mysql.
That is a bad part since you should close the old board during the upgrade so you don't have new posts not imported during the upgrade.
The good part of that is you can do a trial run without impacting your existing board.
Then if it works okay do the real thing first closing your old classic board.
