I have a customer that wants to use basic mode (key system functionality) on an IPO 500 v1. If I upgrade them to R8 can I use Basic Mode without any issues? I guess I am getting confused between Partner Mode and Basic mode... whats the difference between the two? is it just a marketing thing where they changed the name. the end goal is to give them key system functionality with 4 lines and 5 phones. the handsets will be 1416.