Microsoft ships .NET 10 LTS and Visual Studio 2026, Copilot everywhere

Microsoft has released C# 14 and .NET 10, a long-term support version, along with a bunch of related products including Visual Studio 2026 and Aspire 13. Copilot Free is included but devs will soon hit its limits.

The new releases were timed to coincide with the virtual .NET Conf under way this week. It is a big day for Microsoft's developer platform since .NET 10 is a long-term support release, which only come around every two years.

There is also Visual Studio 2026 (VS 2026), the successor to VS 2022, with a refreshed user interface, though perhaps not as big a jump in features as the first name change in years implies.

Nevertheless, there is plenty for developers to chew on in the new batch of releases. C# 14, included in the .NET 10 SDK, introduces file-based apps, meaning applications contained in a single file with a .cs extension. These look a lot like scripts, and support #! directives on Unix-like platforms, enabling invocation via the ./ prefix when marked as executable. This could be useful for utilities, but the thinking behind this is more about attracting newcomers to the language by simplifying the first steps. Single file applications can be converted to full projects using the new command, dotnet project convert.

Visual Studio 2026 has a revamped user interface based on Microsoft's Fluent UI design language, deeper integration with Copilot, and improved performance that might speed loading of large multi-project solutions by up to 50 percent, according to principal product manager Mads Kristensen. Microsoft's Windows-only IDE is regularly updated, though, and there is more difference between the earliest and latest VS 2022 than there is between the latest VS 2022 and the new VS 2026.

As with all Microsoft products, there is a strong push toward use of AI, in this case GitHub Copilot. Developers can get started with Copilot Free, offering up to 2,000 code completions and 50 premium requests per month. That number is not what it seems, thanks to what the company calls multipliers, which mean that a single interaction can use more than one premium request, as we outlined in June. The free Copilot is only intended for individuals, and lacks features such as audit logs, policy management, access control and other business-oriented add-ons. When Copilot Free usage limits are hit, Visual Studio reverts to IntelliCode suggestions and chats no longer respond.

ASP.NET Core, Microsoft's web framework, gets many updates in this release including built-in WebAuthN and Passkey support for modern authentication.

There is also a new release of Aspire, formerly called .NET Aspire, a code-first toolkit for creating and deploying microservice and container-based applications. The name change comes about because it now supports Python and JavaScript applications, though the Aspire CLI (command-line interface) and dashboard showing telemetry remain built in .NET. Aspire makes it relatively easy to orchestrate resources such as Redis caching, database connections, web applications, messaging services, storage services, and more, using an approach that will look familiar to ASP.NET developers, adding services to an application builder.

Aspire is open source and now has a dedicated website. It has some momentum, as indicated by the number of integrations available - 142 at the time of writing. Integrations are required for a service to work smoothly with Aspire, and now exist for products including PostgreSQL, Redis, RabbitMQ, Kafka, MongoDB, Oracle databases, as well as the obvious Microsoft products such as SQL Server and Azure. There is an AWS integration, but overall there's a strong Azure flavor, as one might expect.

The progress of .NET from its Windows-only, closed origins to an open source stack that runs well on Linux and Mac has been remarkable.

Microsoft said at the event that C# is consistently among the top five programming languages in use on GitHub. There are caveats, though. One is that although there are plenty of contributions from outside Microsoft, the future of the stack is dependent on Microsoft and therefore vulnerable to changes in its corporate policy. Another is that the dominance of JavaScript and TypeScript-based applications looks set to grow further, thanks to AI coding assistants tending to default to that unless instructed otherwise.

That said, .NET has made consistent progress since it was open sourced as .NET Core in November 2014, giving developers some hope that Microsoft's investment will continue. ®