What issues should be considered when planning upgrades over a 5 year horizon? What kind of issues should we be planning for? Change in hardware, OS, technoloygy? Does support have a requirement like "stay within two releases of current". Trying to think a head on a CUCM, Unity, UCCX 8.5 deployment. We are migrating to new UC servers for virtualization, but what should we be thinking about 5 years out and planning for now? Welcome all community input.