Ricoh released Image Sync version 2.1.15 with support for the function of the Ricoh GR III and Ricoh GR IIIx cameras to turn the power off directly from the ImageSync app:
Compatible with the function to turn the camera’s power off from the ImageSync app, which will be added to the GR III / GR III x extension firmware update (scheduled to be released in late January). *”RICOH GR III” firmware must be updated to version 1.70 or later to use this version. *”RICOH GR IIIx” firmware must be updated to version 1.20 or later to use this version.