Below is a link to the current firmware update file for the Duet System - M2T transmitter and M2R receiver, plus the DCHT portable transmitter. This is a zip file, after downloading extract it into a temporary folder. Use the Wireless Designer™ program to update firmware, instructions are found here.
Note: This is a link to the Wireless Designer firmware update file, which bundles the latest firmware for multiple products. Wireless Designer will automatically choose the right firmware images from the file.
For the M2T and legacy M2R, there are two firmware choices offering either unencrypted digital transmission (the original mode) or AES-256 encrypted digital transmission (a new mode). The original unencrypted mode firmware is the version 2.x series, and the new encrypted mode firmware is the version 3.x series. If encrypted mode firmware is installed into M2T or M2R units, they are identified in Wireless Designer as M2T-X and M2R-X to indicate that they are operating in encrypted transmission mode. The M2Ra offers both encrypted ("DCHX" compat mode) and non-encrypted ("Duet" compat mode) operation in a single firmware version.
When using version 3.x firmware in a Duet system a recent version of Wireless Designer is required:
Starting with version 09Sep2019, both 2.x and 3.x firmware are available in the same update file. When updating firmware in the M2T or M2R, the Wireless Designer Firmware Update wizard offers a choice between encrypted and unencrypted operation and automatically installs the correct firmware version. You may switch back and forth between them at will, but note that units running 2.x series firmware (unencrypted) and 3.x series firmware (encrypted) are not interoperable. In a Duet system, all M2T and M2R units use either all 2.x or all 3.x series firmware. DCHT versions 1.10 and higher work with M2R receivers using either 2.x or 3.x firmware, while DCHT versions 1.05 and lower work only with M2R receivers using 2.x firmware.