Whereas Sofle v1 & v2 used the ProMicro MCU, Sofle Pico is built specifically for the RP2040 Pico MCU. The Pico offers larger memory options at a low price point. Inexpensive clones are readily available. The increased MCU capacity of the Pico has plenty of space for OLED and RGB animations. Although there is a QMK option to port the legacy ProMicro config to RP2040 boards that are backwards compatible, some RP2040 pins are not 5v tolerant. Essentially, the per key rgb doesnβt always work as it should. There are many RP2040 boards available in the same form factor as the ProMicro, but they tend to be 4-8 times more costly than the Pico form factor, and there are plenty of inexpensive Pico clones. Accommodating the voltage variances between the ProMicro and the Pico required drastic wiring changes which results in the loss of backward compatibility with Sofle v1/v2 firmware. The SK6812MINI-E LEDs commonly used with ProMicro keyboards require 5v logic. The Pico uses 3.3v logic, so it uses a lower current LED variant, specifically the SK6803MINI-E. Thank you to Dane Skalski and the Junco for providing this excellent 3V logic circuit.