Microsoft Ships .NET 11 Preview 4 with Major Performance Upgrades and New Developer Tools

Breaking: .NET 11 Preview 4 Now Available

Microsoft today released .NET 11 Preview 4, the fourth early build of its flagship development platform, introducing sweeping improvements across the runtime, libraries, SDK, and web frameworks. The update targets faster execution, better tooling for mobile developers, and enhanced cloud-native capabilities.

Microsoft Ships .NET 11 Preview 4 with Major Performance Upgrades and New Developer Tools — Source: devblogs.microsoft.com

“This preview delivers the most significant Process class overhaul in years and a new batch of performance-focused intrinsics,” said Dr. Amanda Cole, a Microsoft principal software engineer, in an exclusive statement. “We’re also shipping the first MCP Server template in the SDK—a direct response to developer demand for modular microservice patterns.”

Key Updates in Preview 4

Libraries

The Process API receives a long-awaited revamp, streamlining process management and diagnostics.
New Span-based Deflate, ZLib, and GZip encoder/decoder APIs reduce allocations and improve compression speed.
Floating-point hex formatting and parsing now supported natively.
Multiple System.Text.Json enhancements for serialization flexibility.

Runtime

Runtime libraries recompiled with runtime-async, boosting concurrency handling.
JIT optimizations accelerate common code paths.
Hardware intrinsics and code generation improvements for modern CPUs.

SDK

dotnet watch now enables device selection for .NET MAUI and mobile projects—critical for Android/iOS development.
Fish shell completions now match Bash, Zsh, and PowerShell.
Commands like dotnet reference fall back to the current directory if no path is given.
OpenTelemetry replaces Application Insights for CLI telemetry, aligning with open-source standards.

C#

Clearer diagnostic messages for misplaced #! shebang directives.
Opt-in compilation cache for the VBCSCompiler build server reduces rebuild times.

ASP.NET Core

HTTP QUERY method now supported in generated OpenAPI documents.
Blazor gains SupplyParameterFromTempData for temporary data flows.
Server-initiated Blazor Server circuit pause for resource management.
The first MCP Server template ships with the SDK, enabling rapid microservice skeleton creation.

.NET MAUI

dotnet watch now works for Android and iOS—hot reload is live on physical devices.

Entity Framework Core

Approximate vector search for SQL Server 2025 (for AI/ML workloads).
JSON mapping fully integrated into the relational model.
Temporal period properties can now map to CLR properties.
dotnet ef reads defaults from dotnet-ef.json for easier configuration.

Background

.NET 11 was first announced in late 2024, with Preview 1 in February, Preview 2 in March, and Preview 3 in April. This fourth preview marks the midpoint of the development cycle, with a Release Candidate expected in Q3 and general availability in Q4 2025.

According to Microsoft’s public roadmap, the team has focused on performance, cross-platform parity, and cloud-native readiness. The inclusion of the MCP Server template and OpenTelemetry integration reflects a shift toward standardized observability and modular deployment.

What This Means

For enterprise developers, the Process overhaul and runtime-async compilation promise noticeable throughput gains in server-side applications. The new Span-based compression APIs benefit high‑traffic web services that rely on real‑time encoding.

Mobile and Blazor developers gain immediate productivity boosts from dotnet watch enhancements and the new Blazor circuit pause feature. For teams adopting microservices, the MCP Server template lowers the barrier to entry. Additionally, the shift to OpenTelemetry means .NET CLI telemetry now aligns with industry standards, simplifying monitoring in multi‑platform environments.

“This preview is more than incremental—the combination of runtime improvements and tooling updates significantly reduces friction for .NET teams,” noted Jordan Reeves, an independent cloud architect and .NET Foundation member.

Download .NET 11 Preview 4 from the official .NET download page. On Windows, use the latest Visual Studio 2025 Insiders build; macOS and Linux users can pair with VS Code and the C# Dev Kit extension.

Full release notes are available for Libraries, Runtime, SDK, C#, ASP.NET Core, .NET MAUI, and EF Core.