I recently discoverd iredmail. I started looking at the code a bit and figured the favored database solution is MySQL.
I would rather use PostgreSQL but then, I figure, I would need to get my hands dirty. Are there plans to also support PostgreSQL?
Actually I think PostgreSQL should be the default storage backend anyways. Oracle bought Sun thus they may discontinue MySQL. You don't think so?! ... look what happend to Virtual Iron. .... bought by Oracle, feature migration into Oracles VM platform and then Oracle decided to let die Virtual Iron.