Is there any documentation / manuals out describing the new features in the software upgrades for the PM3?
This is how much Magellan describes about the last upgrade:
ftp://ftp.magellangps.com/Land%20Survey/PM3/PM3V2_1/PM3%20V2.1_Release%20Notes%20revA.pdf
If you do not already have the ProMark3 RTK manuals you can get them from the ftp server at
ftp://ftp.magellangps.com