Porting Razor RockStars to ServiceStack V4

I'm currently looking at the Razor Rockstars example project on github, to try and grasp how ServiceStack V4 and Razor is glued together.

I am specifically struggling with the following piece of code in the SS Razor demo:

SetConfig(new EndpointHostConfig {
           CustomHttpHandlers = {
                { HttpStatusCode.NotFound, new RazorHandler("/notfound") },
                { HttpStatusCode.Unauthorized, new RazorHandler("/login") },
            }
        });

I know from the docs that EndpointHostConfig is now simply HostConfig, but I can't seem to locate the CustomHttpHandlers in the Service Stack V4 release notes. Is there something obvious I'm missing?

Thanks in advance.