Extend WPF and Silverlight Support
You can use WPF and Silverlight Add-in Extensibility SDK to develop support for testing third-party and custom WPF and Silverlight controls that are not supported out-of-the-box
Use Extensibility Accelerator for Web Add-in Extensibility Development
Avoid Downtime Due to License Server Failures
Useful for concurrent license users. With redundant license servers you can create failover, so that if your main license server fails, your remaining servers maintain availability of your licenses without causing any downtime or loss of licenses for users.