Simply follow the original instructions to apply the update. No key is needed to revert to an earlier version. However, you cannot revert to a version prior to version 2.
Um, isn't CC DND an option you can easily turn off in the settings? I don't think you don't have to revert to use the old fashioned CC. Correct me if I'm wrong.
The only two in the radio meau is; CC DND and then CC PRI. In version 2 had interruptions, but CC was active when someone was talking. Now in version 3 CC does not work while someone is talking. Correct me if am wrong please.
For CC all we did was add a mode (CC DND). We didn't take away any modes. If you prefer the CC to be active during other reception, then set the scanner to CC PRI.