The main purpose of this RC is to test new I2C code for Duet WiFi/Ethernet + DueX5 configurations. See https://github.com/dc42/RepRapFirmware/blob/dev/WHATS_NEW.md for the upgrade notes and change list.
Caution! There are known issues with this release when using workplace coordinates (G55-G59). Please do not use this release on CNC machines, or on other machines if use of workplace coordinates is needed - wait for RC3 instead.