Hi,Several years ago Elecraft explained the firmware numbers. Lets use 2.86. The 2 is a major upgrade from 1. The point 86 is a minor or a bug fix. If the point 86 jumps to point 89 it means multiple improvements/bug fixes. Reading the latest fwnotes for an Elecraft product might explain the changes. Hope this helps/explains firmware numbers. 73Jim HK7SSS