
Pair 1x12 Wireless MTB / Gravel derailleurs and Shifters
Pairing 1x12 fully wireless Di2 MTB shifters and derailleurs can be done in two different ways. With the Shimano mobile app, and without.

The new GRX RX717 is Shimano's cheaper version of the GRX 1x12 RD-RX827.
It is a wireless 1x12 long-cage derailleur, that can be paired with any Shimano 10-51T MTB/Gravel cassette.
Just like the 'very' similar Deore M6250 rear derailleur, it features built-in Automatic Impact Recovery, an impact-deflecting shape, and simple covered-pulley solutions. The derailleur stands up to harsh trail impacts and still retains its lightning-quick shifting speed and top-level performance.
The derailleur is fully wireless, with a BT-DN320 battery inside the derailleur. The battery is taken off the derailleur for charging.
RD Protection Function: The new Automatic Impact Recovery function instantly returns the derailleur to its original position after impact. Protected Battery: Tucked safely inside an enclosed space, the battery won’t budge even in rough terrain, while remaining completely removable for charging.
Charging these batteries is easy - you take out the battery, pop it in the charger, and that's it. After about an hour the battery will be fully charged, and you're good to go.

Pairing 1x12 fully wireless Di2 MTB shifters and derailleurs can be done in two different ways. With the Shimano mobile app, and without.

Pairing 12-speed Di2 wireless shift levers can be done using the mobile app, wires, or using the SM-PCE02. This page describes how to pair via mobile phone, and E-Tube EW-SD300 wires.

Unpairing 12-speed Di2 wireless shift levers can be done using the mobile app or using the SM-PCE02 and E-Tube Project for Windows. This page describes both methods of unpairing wireless shifters.