There is no firmware information available for the 851C as the current version is the original and only version ever released. April 03, 2024 10:38 Related articles What devices can I connect to the digital inputs of my 851C? Azur 851C - Technical Specification 851C What is USB Audio? Azur 851C - Manual Where can I find the Evo 75 & 150 - Control4 Drivers