If you own a Fender® MUSTANG™ MS-4 footswitch, or a ULT-4 4-Button Footswitch (used with the G-Dec 30), both will work with the new MUSTANG GT amps. Both footswitches will control the functionality of the Mustang GT in exactly the same manner as the MGT-4 footswitch (which is optional with MUSTANG GT 40 and 100, but included with 200)
Although the functionality is the same on all three footswitches, the labeling on the legacy footswitches differs from the MGT-4. The image below shows the button functionality if you were to use your legacy footswitch with a MUSTANG GT’s. The PDF below also provides an overlay that will print to scale, so that you may cut it out and tape it to your legacy switch.
We will soon be producing and offering, free of charge, a magnetic overlay that you may apply and remove at any time from your legacy switch, however, until it is available, the attached PDF will allow you to use your legacy switch.