Four months after the unveiling of the developer Beta Build of Silverlight 4, Microsoft has made available for download the Release Candidate bits for the next generation of its alternative to Adobe Flash. During the opening keynote address at MIX10, Scott Guthrie, corporate vice president, .NET Developer Platform, announced the release of Silverlight 4 RC Build 4.0.50303.0, emphasizing that the final version was approximately one month away. Guthrie noted that Microsoft was working to wrap up Silverlight 4 the following month, and, in this regard, April 2010 would bring with it the RTW (release to web) milestone for the technology.

“I'm pleased to announce that the release candidate of Silverlight 4 is now available for download […[. We're going to ship the final release of Silverlight 4 next month,” Guthrie stated. “So we're really excited about finishing up the Silverlight 4 release and are looking forward to all the great applications like the eBay app you just saw here that we know you're going to go build with it.”

Microsoft offered the first taste of Silverlight 4 at PDC 2009 in November 2009, offering a developer Build. With the Release Candidate available, developers can get started on the work necessary to adapt older content to Silverlight 4, in preparation of the imminent launch next month. At the same time, Silverlight 4 brings to the table a range of new features, which permit devs to build new experiences for users.

Still, one aspect needs to be emphasized related to just what developers can do with Silverlight 4 RC Build 4.0.50303.0. The official word from Microsoft is that, just as it was the case with the Beta release, the RC milestone is reserved for developers.

“This is a developer release only! This release of Silverlight 4 is a developer release. What this means is that there is no ‘go-live’ licensing available and the end-user runtime of Silverlight 4 is not available. The tools below are intended for software developers only,” the company stated.

Silverlight 4 Release Candidate (RC) Build 4.0.50303.0 is available for download here.