I've just had to move our FusionBB from a server running MySQL 4.something to one running 5.something.
All seemed to be OK, but then I found I couldn't post new messages. It turned out that the 'Post_class' was trying to insert a row with an integer value set to '' (two single quotes) which isn't an integer value.
In MySQL 4, that was converted to '0', but in MySQL 5 it isn't.
I found an article here
explaining how to make MySQL 5 less fussy, which does seem to work, but it doesn't seem ideal to have to do this.
Is FusionBB meant to work with MySQL 5 'strict' mode?
(FusionBB 3.1 Final)