Silverlight is Microsoft's framework for the development of web applications. It was released in 2007 and its most recent release came almost three years ago. As of now, the legacy framework is only supported on Internet Explorer, and that is set to change soon as well. Silverlight is reaching end of support on October 12, 2021, as pointed out by Tero Alhonen on Twitter.
The writing's been on the wall for quite some time now for Silverlight. Silverlight 4 was the primary development platform for Windows Phone, and we all know what happened to that. Even way back in 2011, we had former Microsoft executives proclaiming the death of Silverlight. Netflix transitioned from Silverlight to HTML5 in 2013 too. Microsoft Edge does not support Silverlight outside of IE mode, Google Chrome ended support for it in September 2015, and Mozilla Firefox did the same in March 2017.
Microsoft says that until the end of support date on October 12, it will continue providing technical assistance to customers using Silverlight 5 only. This includes paid support for Silverlight applications running on Internet Explorer 11 (IE11) on the following platforms:
- Windows 10
- Windows Server 2016
- Windows 8.1
- Windows Server 2012 R2
- Windows Server 2012
- Windows Embedded 8.1 Industry
- Windows Embedded 8 Standard
- POSReady 7
- Thin PC 7
Microsoft has emphasized that it is not planning any move to kill off Silverlight applications but it is important to note that software running on this framework will not get any security or feature updates. Similarly, customers who purchased Silverlight perpetual licenses are still legally licensed to utilize it, without support. No customer is eligible for extended support past October 12, even if they offer to pay for it. The company has also warned that the perpetual Silverlight license cannot be redistributed.
After the aforementioned date, the Silverlight portal will still be accessible, but it will not offer an installer. For web-based applications, Microsoft has recommended Blazor as an alternative, while WinUI 3 with Windows App SDK has been encouraged if you're considering moving to a desktop-based application not dependent upon the browser.
Although Internet Explorer 11 - the last browser that currently supports Silverlight - is being phased out, Microsoft says that Silverlight apps will continue to work in IE mode in Edge.