The Raspberry PI 4 still needs RPI_WS281X. The fix is on line 18 of Led.py: < if self.pcb_version == 1 and self.pi_version == 1: > if (self.pcb_version == 1 or self.pcb_version == 2) and self.pi_version == 1: Or simply "if self.pi_version == 1:"