There was a change (and I cannot tell you what version it happened at) where they added more audio tweakers to the programming software. In KPG-111D if you go to NXDN>GENERAL 2 and under audio you can select Function Type as either enhanced or standard, then you have the latest and greatest as far as audio control for the radio (NXDN only, not for analog).
If you are wondering what the latest firmware gives you, here's a bulletin that has the info.
https://dl.dropboxusercontent.com/u/2991846/P-13-08LM_NEXEDGE_Version_4.0.pdf
Chances are it really doesn't pertain to what you use the radio for, or maybe so?