The Application Request Router (ARR) has been officially released and is available for free download, supporting all versions of IIS7. Application Request Routing (ARR) is a proxy-based routing module that can forward HTTP requests to content servers based on HTTP headers, server variables, and load balancing algorithms. It can enhance the efficiency and scalability of applications, better utilize content server resources, and simplify application deployment, including pilot management and A/B testing. ARR also has a feature called shared hoster, which modifies how currently offered shared hosting is shared, adding extra services for customers. For more detailed information about ARR, please visit IIS.net/extension.