Multicast capabilities and offline digital rights management are key features in the Silverlight upgrade Credit: StockStudio Aerials / Shutterstock Microsoft this week will shed some light on a planned upgrade to Silverlight, its browser-based rich Internet application technology, which will gain native multicast support capabilities as well as support for offline digital rights management. Called Silverlight 4, the upgrade will be previewed at the International Broadcasting Convention, which begins Sept. 11 in Amsterdam. Microsoft, which shipped Silverlight 3 in July, has not revealed a ship date for Silverlight 4. [ Check out the related First look: Microsoft Silverlight 3 challenges Adobe AIR ] Multicast capabilities in version 4 will provide a way to stream video on bandwidth-constrained networks, thus reducing the burden on media servers while enabling broadcasters to reach more viewers, according to a Microsoft representative. Previously, a plug-in was required to enable this functionality. Offline digital rights management in Silverlight 4 will be powered by Microsoft PlayReady technology. PlayReady is intended to enable the mobile industry to support online content services. With offline PlayReady DRM and out-of-browser capabilities in Silverlight 4, movie studios and retailers can offer the same rich interactive experiences via digital copy and Internet distribution as consumers get with DVD or Bluray, Microsoft said. Silverlight 4 will enable movie studios to offer network-delivered updates, special offers, and live events. The company this week also will announce plans to release IIS (Internet Information Services ) Media Services 3.0, enabling delivery of interactive “Live Smooth Streaming,” which has been used to broadcast live events. IIS Media Services, which is an integrated HTTP-based media delivery platform that supports HD streaming, and Silverlight 3 provide a platform for delivering online media experiences for online consumers, Microsoft said. Microsoft this week announced a beta version of its Smooth Streaming player development kit, which is intended to make it easier for developers to build custom players using templates. It will be offered with the release of IIS Media Services 3.0. Microsoft this week also will publish the IIS (Internet Information Services) Smooth Streaming Transport Protocol and PIFF (Protected File Format) specification, for DRM interoperability, under the Microsoft Community Promise, thus allowing use of the technologies without Microsoft invoking any claims against users. With these moves, Microsoft hopes to promote industry adoption of a video format optimized for Internet delivery and interoperable among a range of consumer devices. Software Development