I have been looking at moving from 2.1 to 3.1 but as I have 20 series (DT Phones) this is a little difficult and costly. I am not sure what benefits this will give me. Currently I have 3 x DT units on a 412 with about 60 Digital phones, some phone (Alog) units, s08 units, 1 x PRI, VM PRO on IP office mode, Phone manager pro + iphone manager lics and a remote site with a 403DT using SCN. I know I need to replace the phones and DT Modules along with the 403DT which I can arrange with my maintainer but I need to give good justification to do this. What are the benefits that you guys can think of and is it worth it?