vBulletin upgrade question -

[MixMakers]

I'm looking to upgrade vb 3.5.x to 3.8. I have a fairly large forum with over 1.5 million posts and I was wondering what would be the quickest/safest way to smoothly upgrade. I was also wondering if I could possibly upgrade everything to a test directory first?

[dismas]

Your vB license allows for one test board. Generally people install this into www.example.com/testvb/ So you could install 3.6.8 (note: 3.6.8 is the lastest stable version, 3.8 doesn't exist) into the test board, test all your styles/hacks/etc. and then do the upgrade of your live board.