This release fixes bugs in release candidate 2 and adds support for a scanning Z probe to be used as a regular Z probe if appropriate temperature compensation is set up. See https://github.com/Duet3D/RepRapFirmware/wiki/Changelog-RRF-3.x-RC#reprapfirmware-350-rc3-changes-since-rc2 for upgrade notes and the change list.
Use of Duet with attached Single Board Computer, please upgrade from the package server as usual. Users running in standalone mode, use the files here.