Mustang GT Support Click here or go to https://www.fender.com/tone/support to visit the Mustang GT and Tone support home. Related articles Effective March 20, 2020 Fender® FUSE™ has been discontinued. How do I update the Firmware on the Mustang LT amplifier? How do I update the firmware on a Mustang GT or Rumble digital amplifier? Fender Tune Support has a new home! Rumble Stage and Studio Support