T4 to T3 Adapter - pixelmatix/SmartMatrix GitHub Wiki

An adapter has been designed to take a Teensy 4.0 or Teensy 4.1 and directly connect to the SmartLED Shield (V4) for Teensy 3. It can be custom ordered from OSH Park, although some assembly is required.

See this forum post for details: https://community.pixelmatix.com/t/teensy-4-0-released/498/32

Note the adapter differs from SmartLED Shield for Teensy 4 (V5) in the default pin used for CLK

Todo: describe the jumper configuration options