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 PDF below provides an overlay that will print to scale, so that you may cut it out and tape it to your legacy switch. The image below shows the the button functionality if you were to use your legacy footswitch with a MUSTANG GT using the overlay.
If you would like a magnetic overlay*, free of charge, that you may apply and remove at any time from your legacy switch, please contact customer support to request one.
*While supplies last