This version requires a new LF roll-off digital potentiometer on the audio board for more accurate placement of -3dB points for the six roll-off settings. This version is not compatible with the old digital pot. The pot in question is U22, which was formerly SID5201/10K and now must be SID5200/50K.
This version also requires that the RF board use the new National LMX2485 PLL. Use version 1.x, and the older digital pot on the audio board, with RF boards that use the old National LMX2353 PLL.