Hello,
Because we use hibernate we should theoretically work against all the databases that hibernate connects to.
We have our software running against both MySQL and Oracle in house, and for the October release are currently planning to certify the software against MySQL, with the Oracle certification coming in December.
For the paid for support point of view, the certified databases will be the ones we support (although I am sure that given the right circumstances this would be flexible), but for the free forum support we would endeavour to help anyone using any hibernate supported database.
Steve