I'm currently running Cent OS 5.1 with ZCS 4.7 Open Source edition on a Dell Poweredge that is about six years old. It has two 1ghz Pentium 4 processors and 1 gig of RAM and ultra wide SCSI drives. I've been running it for about 5 months with no problems, though the Ajax client seems slow (though that may just be the Ajax, not the server). Obviously this is below the suggested requirements, but since I've got four users and will never have more than 10 users (it is my family email server), what do you think about moving up to the latest ZCS Open Source edition? Any suggestions?