Looking at the script from the repo you installed 6.2.4. This isn’t the most recent. I think you’d be fine to update (it’s just extracting an exe and a couple dolls to your game directory). I’ve never heard of a mod requiring an older version, so staying with the most recent is probably good practice!
I think my favorite part is how they’ve brought back software rendering, both by allowing it on linux and by giving the option to turn off texture filtering on opengl. That plus making the main menu look like the original release brings me right back to how I first played Half-Life!