.NET 11 in depth: Runtime, libraries, and SDK for the AI era | OD806
Microsoft Developer presents an in-depth Build 2026 session on .NET 11 improvements across the runtime, libraries, and SDK, with a focus on performance, diagnostics, and developer productivity. It also highlights work that supports intelligent, cloud-connected, and agent-driven apps, plus concrete library updates like Unicode and JSON enhancements.
Overview
This session (OD806) walks through key .NET 11 investments that aim to make modern .NET apps faster, easier to diagnose in production, and more efficient to ship and run.
Ecosystem work: making the CLI and libraries Trim/AOT friendly
- How .NET 11 continues the push to make the .NET CLI and core libraries friendlier to:
- Trimming (reducing app size by removing unused code)
- Native AOT (ahead-of-time compilation)
- Why these changes matter for modern app scenarios where startup time, memory footprint, and deployment size are important.
Telemetry modernization and trim-friendly patterns
- Technical challenges involved in migrating to modern telemetry approaches.
- Patterns and guidance aimed at keeping telemetry and diagnostics compatible with trimming.
Tracing and performance monitoring with OpenTelemetry and Aspire Dashboard
- How .NET 11 aligns with OpenTelemetry for tracing and monitoring.
- Using the .NET Aspire Dashboard for observing traces and performance signals.
SDK acquisition and download optimizations
- Improvements to the SDK acquisition and download process.
- Focus on reducing friction and improving reliability/speed when getting the right SDK.
Text processing enhancements and Unicode validation APIs
- Updates to text processing in .NET 11.
- New Unicode validation APIs.
- Explanation of UTF-16 limitations and how Unicode code points relate to those limitations.
System.Text.Json updates
- A new property override related to JSON naming policies.
- Introduction of JSON Lines support:
- JSON Lines (JSONL) as a format for newline-delimited JSON records.
Debugging async behavior: nested async and stack traces
- A sample application demonstrating nested async behavior.
- How stack traces surface in these scenarios and what to look for when diagnosing issues.
Resources
- .NET 11 download and info: https://get.dot.net/11
- Microsoft Build sessions: https://build.microsoft.com