Microsoft quietly rolls out Silverlight 5.1

Microsoft quietly rolls out Silverlight 5.1

Summary: Microsoft made available for download Silverlight 5.1 on May 8. Here's what's included in this minor update.


As part of the Patch Tuesday updates delivered on May 8, Microsoft quietly delivered a minor refresh to Silverlight.

The new version (called in one place on Microsoft's Web site 5.1, but which actually seems to be 5.2) is the first Silverlight update Microsoft has delivered since December 2011, when it rolled out Silverlight 5.

Update: Actually, the update seems to be 5.1 and not 5.2. Folks who are downloading it are reporting it is showing up as 5.1. So the 5.2 seems to be the typo on the Microsoft site. I've asked Microsoft to confirm the version number. Still no official word so far.

Silverlight fans shouldn't get too excited and consider the 5.1 update as evidence that Microsoft plans to continue to put efforts into furthering its Silverlight browser plug-in and Web, desktop and mobile development platform. Microsoft occasionally advances the version number of some of its products -- Internet Explorer, for example -- when it delivers a patched and updated version as part of its Patch Tuesday set of security updates and fixes.

What's new in Silverlight 5.1?  Here's a list of some of the updates, which include performance, reliability and security improvements, according to Microsoft:

  • Fixes Security issue described in the following Microsoft Knowledge Base article:
  • 2636927 MS12-034
  • Fixes an issue where “Best Effort” Silverlight Digital Rights Management Output Protection levels failed on some machines.
  • Fixed a failure to update OOB (out of browser) applications that are configured to use elevated trust when in browser.
  • Fixes an issue where persistent license acquisition would fail when a customer upgrades from Silverlight 4 to Silverlight 5.
  • Fixes an issue where certain character combinations can cause Silverlight application to crash.
  • Fixes an issue where Silverlight would not play content which required Output Protection.
  • Fixes a Silverlight DRM issue where some customers encounter hardware ID mismatch errors which can only be resolved by re-individualization.

Microsoft officials have continued to decline to comment on the future of Silverlight beyond the Silverlight 5 release. Inside and outside the company, the word is that Silverlight 5 (and its various minor updates) will be the last major version of the platform. Microsoft said in December that the company will support Silverlight 5 until 2021.

Topics: Security, Browser, Microsoft, Software Development


Mary Jo has covered the tech industry for 30 years for a variety of publications and Web sites, and is a frequent guest on radio, TV and podcasts, speaking about all things Microsoft-related. She is the author of Microsoft 2.0: How Microsoft plans to stay relevant in the post-Gates era (John Wiley & Sons, 2008).

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  • OOB

    I think OOB (Out of Browser). A quick fix! Well, maybe not, you did mention in Browser???
    • Perhaps...

      Perhaps the 'box' is the browser window?
    • OOB

      Oops. Bet you are right. I will fix that. Thanks! (Too many OOBs :)) MJ
      Mary Jo Foley
  • "quietly" - I think not

    To "quietly" roll it out would have included NOT pinning the Silverlight program icon on the start menu as if it's one of my most needed programs that I use every day.

    At least they didn't pull an Adobe and stick the darn thing on the desktop too.
  • Silverwhat ?

    I thought the poor fellow's funeral happened months ago.
    Alan Smithie
  • Silverlight

    Silverlight is Flash's smarter, faster, better looking cousin. Both are doomed for HTML5.
    • Too true

      For all the buzz about HTML5, there are still some types of applications for which a technology such as Silverlight is far superior. Namely, I'm thinking of line-of-business applications with extremely rich user interfaces, especially those that need to integrate with existing websites. I was recently the tech lead over a moderately large enterprise application, and after POCs we determined that building the front-end in HTML4 was impossible, but even HTML5 would take approximately twice as long (and twice the money) as using Silverlight. HTML5 does reduce the set of applications that NEED a browser plugin, but it's far from eliminating that need.

      It does seem as though the Windows 8 Metro apps are aiming to fill the role of Silverlight, but that's not a realistic option for enterprises. Surprising as it may be, some people actually do use Mac, and sometimes web delivery is a requirement!

      Coming from the perspective of a developer, I love what HTML5 improves relative to HTML4, but it would be very unfortunate if that becomes the only viable option to build all web-based apps. Competition between platforms helps all platforms drive forward.
      • I agree completely

        I still believe that Silverlight has a role to play in building LoB apps for web browser deployment. It will take some considerable time for Windows 8 and Metro app delivery to take hold in enterprises (where a *surprising* amount of development really does take place versus AppStore development for consumers).

        I've yet to see any major advances in Visual Studio tooling to let developers build the kind of rich UI in HTML 5 that Silverlight development offers today.

        I'm surprised there isn't more analyst comment along the lines of asking where is the rich HTML 5 tooling for enterprise development in Visual Studio? And where is the Designer/Developer support for HTML 5 web applications in Expression/Visual Studio?

        With so much emphasis on Windows RT development, I think this important requirement is being massively overlooked.
      • Too true

        And without Silverlight and even some marketers making half-truth claims of their competitor known as "Flash", Adobe had to step up to improve the Flash Player (v11 being rather better than its predecessor and it does run great on my Droid Razr to be sure... and it's nice to play Canabalt for free...)
    • How so?

      Have you programmed both platforms extensively, or are you just making blind assumptions? Care to share some details?
  • Why are still pushing Silverlight 4 upgrades to Windows Update and not Silv

    Why are still pushing Silverlight 4 upgrades to Windows Update and not Silverlight 5? You have to download that manually.
  • Important one for customers!

    Fixes a Silverlight DRM issue where some customers encounter hardware ID mismatch errors
    beau parisi
  • Silverlight and Powerview...

    I listen to windows weekly religiously each week where it is frequently mentioned that MS is not confirming or denying support future version of Silverlight. This puts them in a conundrum since PowerView which has just been release in SQL Server 2012 is based on Silverlight. This is not to say that they cannot replace it in future versions with something newer (possible HTML5?) and we are just in a transition stage since the SQL Server Team has to choose an appropriate technology several; year ago in Silverlight was it.. thoughts?