In 2021 the Servo I underwent a redesign. H-Bridge Drivers that were used for over a decade in the Servo I reached their end-of-life. Firmware for the V1 and the new V2 are very different and not interchangeable. Below are links to both versions. If you purchased your controller anytime before 2021, you need V1 firmware. V1 controllers are also identifiable by having a serial number lower than 57200. V2 controllers were sold from 2021 onward and have serial numbers greater than 57200.