News

Microsoft Releases .NET Framework 4.5.1

64-bit Edit and Continue is the key feature addition.

Related Content:

On the same day Microsoft released the final version of Visual Studio 2013, a less-heralded but critical product for developers also got its official edition: the .NET Framework 4.5.1.

The latest version of .NET is a "customer-focused release", states a blog entry from the ".NET Team" from earlier today. Rather than a raft of bug fixes, this version is more about adding features.

The top feature added was by far the most requested by developers: X64 Edit and Continue (EnC). The delay in adding it, according to the blog, was the necessity to get other features in place first:

"We've wanted to add that feature for a long time, but we always had at least two other features ahead of it in our priority list. This time, we decided that it really needed to get done and didn't bother with any of the priority lists."

X86 EnC has been around since the days of Visual Studio 2005 and the .NET Framework 2.0. But there has been no 64-bit version until now. With X64 EnC, a developer can stop at a breakpoint with edited source in an invalid state. The source can then be made valid, followed by the developer stepping again and continuing to run the application.

The blog pointed to numerous other upgrades as well, including:

Microsoft calls the .NET Framework 4.5.1 a "highly compatible, in-place upgrade" from .NET 4 and .NET 4.5. It's available from the Microsoft Download Center. The Preview version of .NET 4.5.1 was released June 26 of this year.

A key feedback driver for the .NET Framework and Visual Studio products is the Visual Studio UserVoice site, which allows developers to request features, and other developers to vote on them, signifying their agreement with the request. The UserVoice requests that were fulfilled with .NET 4.5.1 are X64 EnC; function return value in the debugger; sorting and filtering in the Code analysis window; and Large Object Heap (LOH) compaction.

About the Author

Keith Ward is the editor in chief of Virtualization & Cloud Review. Follow him on Twitter @VirtReviewKeith.

comments powered by Disqus

Featured

  • Using Local AI to Cut Copilot Usage-Based Billing Shock

    After being gobsmacked by the new billing plan using almost all my monthly credits in one or two days, I tried pushing some Copilot-style coding work onto local models in VS Code. What I found was less "free AI" and more "pick your pain": cloud charges on one side, heavy local resource use and long waits on the other.

  • .NET 11 Preview 5 Focuses on Performance, Productivity and Safer Code

    .NET 11 Preview 5 focuses on under-the-hood runtime performance gains, streamlined APIs and language features that reduce boilerplate, plus built‑in security checks and incremental ASP.NET Core and EF Core improvements aimed at everyday developer productivity.

  • VS Code 1.124 Focuses on Agent Autonomy and Parallel Sessions

    Microsoft's June 2026 VS Code update turns on Autopilot by default and adds background sending for agent sessions.

  • Developing Agentic Systems in .NET: From Concept to Code

    ZioNet founder Alon Fliess previews his Visual Studio Live! San Diego session on building true agentic systems in .NET -- covering the cognitive loop, MCP tool integration, multi-agent orchestration and enterprise hosting and governance with the Microsoft Agent Framework.

Subscribe on YouTube