Official firmware for the VOTER/RTCM has been moved out of development and into general availability as the latest release v3.10.
You can find the necessary files here: https://github.com/AllStarLink/Voter/releases/tag/v3.10
Instructions for how to upgrade can be found here: VOTER/RTCM Firmware.
This is a recommended update to provide better interaction with the attached GPS in voting applications, as well as improved status and diagnostic information for all uses.