This release makes it easier to flash B-side firmware on the custom boards. OpenOCD/picoprobe and non-standard USB cables are no longer required. Now you just flash the A side with remapper_board.uf2 and then click "Flash B side" on the web config tool. In the future it would be nice to eliminate that last step and make it automatic.
(It also works on the dual Pico version, but you have to connect two additional wires: GPIO2 on board A to SWCLK on board B and GPIO3 on board A to SWDIO on board B.)