Hi, we are a 4,000 user base with mainly v605080 client running on v7.2.1 server and it happens to work fine. We plan to upgrade the clients first ahead of the server to 7.3 using MS config Mgr, then the server over a weekend so Monday morning the versions match. The standard Mitel upgrade process of server first then 4,000 users get a message to d/l a new client on a Monday morning is 1) crazy 2) doesn't work for us as we don't give our users rights to install. We test the mis-matched environment beforehand of course.