Updated Blazor browser support for .NET 5

.NET 5 introduces a variety of new Blazor features, some of which are not compatible with certain older browsers. We are updating the list of browsers supported by Blazor in .NET 5 accordingly.

In .NET 5 we will no longer support Blazor Server with Microsoft Internet Explorer 11. Note that Blazor WebAssembly was already not supported with Microsoft Internet Explorer 11.

There are also known incompatibilities in Blazor Server and Blazor WebAssembly with Microsoft Edge Legacy in .NET 5 that we do not plan to address. The new Microsoft Edge based on Chromium is supported and is recommended instead.

Version introduced

5.0

Old behavior

Blazor Server previously supported Microsoft Internet Explorer 11 with sufficient polyfills. Blazor Server and Blazor WebAssembly were also previously functional in Microsoft Edge Legacy.

New behavior

Blazor Server in .NET 5 will no longer be supported with Microsoft Internet Explorer 11. Blazor Server and Blazor WebAssembly are also no longer fully functional in Microsoft Edge Legacy.

Reason for change

New Blazor features in .NET 5 are not compatible with these older browsers and use of these older browsers is diminishing. Windows support for Microsoft Edge Legacy is also ending on March 9, 2021 and Microsoft 365 apps and services will end support for Microsoft Internet Explorer 11 by August 17, 2021.

Recommended action

We recommend upgrading from these older browsers to the new Microsoft Edge, which is fully supported. For Blazor apps that still need to continue to support these older browsers, we recommend using .NET Core 3.1 LTS. The set of supported browser platforms for Blazor in .NET Core 3.1 LTS remains unchanged and is documented here: https://docs.microsoft.com/aspnet/core/blazor/supported-platforms?view=aspnetcore-3.1.