How to handle custom errors handling in ASP MVC 4+ and IIS 7+

gistfile1.cs

<system.web>
    <customErrors 
        mode="RemoteOnly"
        
        // ResponseRewrite would be a better way, but is uses Server.Transfer so we have to use
        // ResponseRedirect which redirects whole page. To do this better you have to wrap 404 errors
        // in Application_Error
        
        redirectMode="ResponseRedirect" 
        defaultRedirect="Error">
        
        <error statusCode="404" redirect="~/errors/ups/404"  />
        <error statusCode="500" redirect="~/errors/ups/500"  />
    </customErrors>
</system.web>

<system.webServer>
    <httpErrors errorMode="Custom">
        <remove statusCode="403" />
        <error statusCode="403" responseMode="ExecuteURL" path="/errors/ups/403" />
        
        <remove statusCode="404" />
        <error statusCode="404" responseMode="ExecuteURL" path="/errors/ups/404" />
        
        <remove statusCode="500" />
        <error statusCode="500" responseMode="ExecuteURL" path="/errors/ups/500" />
    </httpErrors>
</system.webServer>