I am in the middle of a messy migration, I have a running active 3.2 live and a development 3.3.4, unfortunately we have been testing hard on the 3.3.4 so I cannot simply migrate the forum data.
My plan was to move the transfer the current database and upgrade using the SQL commands, the other option (which might be easier) would be to export the data from the 3.2 and import it to 3.3.4 however this might take longer.
The tricky part is that I only want to migrate some tables as we have done quite a lot of work on the new one e.g. setting up forums, settings, etc.
I know what tables I want to move, so really I just need to know the upgrade commands would be from 3.2 > 3.3.x