I have a customer that is migrating from Siemens Phonemail 6.4 to Unity Connection 7.1. They do not necessarily want to do a flash cutover for 4000 users at their headquarters. Is AMIS my only option or do you know if Phonemail 6.4 supports VPIM? I haven't found any specifics on either Siemens website or through the IETF's Internet RFC 3801.