Upgrading to 6.1 will re-assign line numbering 1-30, 31-60, 61-80 etc for analog lines and 157 up for target lines. Remember if you have voice mail, the AA has to be changed to the new line numbers.
6.1 acts the same as earlier versions of MICS. Auto HF and prime to pool will select a pool trunk, not i/c.
Wannabe.... are to trying on a T7316E set? The HF key has moved to its proper location below the volume bar, not on the bottom of the key column