As CSP evolved, modders started building features that required specific CSP versions. Eventually, server hosts began using a feature within CSP that checks the .
isn't a bug; it's a handshake between two eras of modding. The game is technically "obsolete," but the community has built a life-support system so robust that it outpaces modern sims in features.
If you check your Steam properties, the final public build of Assetto Corsa (including all DLC) is (or v1.16.3 for some legacy branches). Kunos Simulazioni stopped developing the title years ago to focus on Assetto Corsa Competizione . So why is a server demanding a version that is lower than the current Steam build?