I noticed that over time the ZDB files seem to change and those are the ones active. Left over are old ZDB files from each BES user. It seems ZCB recreates the database file for what ever reason but leaves the old one behind. The "old" files are not modified any more. Seems to me I can delete these files without any harm.

Does this sound correct? As long as that ZDB file is not in the BlackBerryServer profile?

For example:
BlackBerryServer(USER)37.zdb (active and actively being modified)
BlackBerryServer(USER)37.idm (active and actively being modified)
BlackBerryServer(USER)37_GAL.idm (active and actively being modified)
BlackBerryServer(USER)21.zdb (old? not currently being modified)
BlackBerryServer(USER)21.idm (old? not currently being modified)
BlackBerryServer(USER)21_GAL.idm (old? not currently being modified)

I noticed this with ZCB 6.0.8. I just upgraded to 6.5.3 but this was happening before the upgrade. I cannot tell if its happening still with 6.5.3.