.NET 10 LTS is here. Microsoft released it on November 11, 2025, and shipped the 10.0.1 servicing update on December 9, 2025. If you’re running .NET 8 LTS or .NET 9 STS, the move to .NET 10 LTS isn’t just a nice‑to‑have—it’s your ticket to three years of predictable fixes, security updates, and platform stability. This guide distills what changed, what to watch, and a practical 45‑day plan to upgrade without stalling your roadmap.
Why .NET 10 LTS matters right now
Dates first, feelings later. .NET 10 is an LTS release—supported through November 2028. .NET 8 LTS stays supported until November 2026, and .NET 9 (STS) also ends in November 2026. That gives you runway, but the servicing train has already left the station with 10.0.1. The longer you wait, the more drift you’ll accumulate across SDKs, CI, containers, and dependencies.
On the feature side, the headliners are practical, not flashy: C# 14 quality‑of‑life gains, ASP.NET Core 10 performance and observability improvements, and Entity Framework Core 10 capabilities that line up with modern data stacks (think JSON columns and vector‑friendly patterns with current SQL engines). Visual Studio 2026 shipped in lockstep, so the tooling story is solid on day one.
The .NET 10 LTS upgrade playbook (45 days)
Here’s how I’ve been steering teams through production upgrades: time‑boxed, risk‑based, and measured. Treat this like a sprint‑and‑stabilize effort rather than a multi‑month refactor.
Days 1–5: Inventory and risk ranking
Make a canonical list of every .NET app and service, including version, workload (web/API, worker, desktop, functions), hosting model (containers, VMs, PaaS), platform dependencies (SQL, Redis, Kafka), and third‑party packages. Assign each a risk band: low (internal tools), medium (customer‑facing but low blast radius), high (revenue‑critical). This determines rollout order and test depth.
Pull the current SDK mapping via global.json files and CI images. Capture your minimum OS/runtime baselines for Windows and Linux nodes. Note any self‑contained deployments or Native AOT experiments you’ve carried from .NET 8/9.
Days 6–10: Pre‑flight environment readiness
Install the .NET 10 SDK on dev boxes and CI runners. Upgrade to Visual Studio 2026 or ensure your JetBrains/Rider + SDK matrix matches your global.json strategy. In CI, add a parallel .NET 10 job without removing the existing lane; you want green builds before you cut over. For containers, pull official .NET 10 images and pin to a digest to avoid surprise base updates.
If you’re targeting Arm64 in the cloud, validate Arm images early—build once, run on Graviton or Ampere nodes, measure cold‑start and throughput deltas. If you’re exploring Arm in AWS, our Graviton5 migration playbook covers the ops angles you’ll hit in staging.
Days 11–20: Dependency triage and code scan
Upgrade first‑party Microsoft packages to the .NET 10‑aligned versions—ASP.NET Core 10, EF Core 10, and the Azure SDKs you consume. Then triage third‑party libraries: look for packages that reference older SDKs, include native shims, or hook deep into Kestrel or the GC. Replace abandonware. Where an upgrade isn’t available, isolate the dependency behind a small adapter and keep your calling surface narrow; this makes later swaps painless.
Run static analysis and threat modeling while you’re in there. If your team deals with JavaScript frameworks too, align security hygiene across stacks—our Next.js patch runbook shows the “patch, verify, prevent” loop we expect from modern web teams. The same discipline applies when you move major .NET versions.
Days 21–30: Project migration and compile
In a branch, bump TARGETFRAMEWORK to net10.0 and let the compiler tell you what hurts. Expect a few API nips: obsolete members finally removed, stricter nullability, and more warnings as errors if you’ve turned on analyzers. Fix forward—don’t fight the compiler. Keep the branch scoped: project files, package references, and the minimum code changes to get a clean build.
When the builds are green, push a signed prerelease to an isolated staging environment. Capture startup, P95/99 latency, memory, and CPU with the exact same load as your baseline. If anything drifts by more than 5–10%, open an investigation ticket immediately; this is where thread‑pool, HTTP/3, or GC configuration tweaks usually pay off.
Days 31–40: Framework‑specific tuning
ASP.NET Core 10. Validate Kestrel settings (HTTP/2 vs HTTP/3, TLS policies), response compression, and logging sinks. If you rely on custom middleware that inspects raw request bodies, re‑test with chunked and g‑zipped payloads to avoid subtle parsing regressions. Keep an eye on request buffering behavior with large uploads.
EF Core 10. If you’re adopting JSON columns or vector‑style search in modern SQL engines, add targeted integration tests. Confirm indexes are created as expected and that provider versions match server features. Run a flyway/liquibase dry‑run of your schema migrations before a single production write happens under .NET 10.
Native AOT. Treat it as an opt‑in per service, not a global default. AOT can shrink cold start and memory for worker apps and some APIs, but reflection‑heavy libraries (polymorphic JSON, DI container magic) may need trimming hints or won’t play nicely. Benchmark first, then decide.
Days 41–45: Progressive rollout and verification
Use a canary. Ship to 1–5% of traffic behind a feature flag or a dedicated pool, bake for at least 24 hours, then ramp. Guardrails matter: health probes, circuit breakers, and an auto‑rollback that your on‑call actually trusts. During the bake, correlate logs and traces across both the old and new runtime pools so you can pinpoint regressions fast.
What might break (and how to avoid it)
Global.json drift. If you pin SDKs tightly, devs and CI images can silently diverge. Surface the intended SDK via global.json, fail builds on mismatch, and teach your team to run dotnet --list-sdks before they report “it works on my machine.”
Analyzer upgrades. Newer analyzers and rules can flip warnings to errors. Decide your policy: either temporarily lower severity for the migration branch or fix the violations now. I prefer fixing anything with correctness or security implications and deferring style‑only changes.
Package binding issues. Transitive dependencies can pull in older assemblies that behave differently on .NET 10. Use dotnet list package --include-transitive to expose the chain, then add explicit references to pin versions during the migration window.
Hosting model assumptions. Linux distros and Windows SKUs matter. If you’re running on managed services, verify that your PaaS or managed Kubernetes nodes have .NET 10 runtimes available and patched (10.0.1 as of December 9, 2025). For self‑contained deployments, test container image size and startup deltas; compress layers and remove build tools from runtime images.
Data you can take to the CFO
• .NET 10 is an LTS release with support into November 2028. That buys three years of predictable fixes and security updates.
• The first servicing update (10.0.1) landed December 9, 2025, signaling an active patch cadence you can plan around.
• .NET 8 LTS and .NET 9 STS both reach end of support in November 2026. Staying put means compressing your upgrade window later—when you’re busier and risk tolerance is lower.
• Visual Studio 2026 aligns with .NET 10 and C# 14, so you’re not waiting on tooling. If your team uses AI assistance in the IDE, manage usage and cost controls—our guidance on taming Copilot Premium Requests applies directly here.
People also ask
Do I have to adopt C# 14 to move to .NET 10 LTS?
No. You can target .NET 10 while keeping your language version pinned. That said, evaluate enabling C# 14 for projects where new features reduce boilerplate or improve correctness. Make it a per‑project decision.
Will ASP.NET Core 10 force me onto Native AOT?
Not at all. Native AOT remains opt‑in. It’s great for certain worker services or APIs where cold start and memory are the bottlenecks. For reflection‑heavy apps, a regular framework‑dependent deployment is often simpler.
Is .NET 8 LTS still safe for 2026?
Yes—until November 2026. But consider the opportunity cost: deferring the move means your 2026 roadmap will carry a bigger migration, likely under tighter time pressure.
Let’s get practical: the 7‑point migration checklist
1) Set the target. Add a clear goal and date: “All production services targeting net10.0 by Day 45.” Publish it in your runbooks and dashboards.
2) Pin and prove tooling. Update Visual Studio 2026 or your editor toolchain, set global.json, and run a smoke build on CI with the .NET 10 SDK.
3) Upgrade dependencies. First‑party packages first (ASP.NET Core 10, EF Core 10), then third‑party. Replace unmaintained libraries now.
4) Build a migration branch. Bump target frameworks, fix compiler errors, and keep the diff focused. No unrelated refactors.
5) Benchmark parity. Compare .NET 8/9 and .NET 10 under identical load. Investigate >10% regressions before rollout.
6) Stage and canary. Ship to a small slice of real traffic with auto‑rollback tied to SLOs.
7) Close the loop. Document changes, update golden paths, and add a monthly “SDK freshness” check to your engineering rituals.
Tooling and CI/CD tips that save an entire sprint
Build images. Create dedicated build and runtime images for .NET 10. Bake in SDKs, Node (if you build SPA assets), and your exact package managers. Tag by date and digest.
Parallel pipelines. Don’t rip out the old lane. Run dual deploys to staging: net8.0/net9.0 vs net10.0. This lets you attribute perf changes to the runtime, not the traffic pattern.
Analyzer gates. Add a CI job that runs dotnet format and your analyzers with the new SDK. Fail fast on security‑relevant rules; collect the rest as warnings for follow‑up.
Observability first. Turn on distributed tracing for the migration window even if you plan to dial it back later. The visibility is worth the transient cost.
Sharp edges we’ve already hit in the wild
HTTP pipeline surprises. Teams with custom reverse proxies or aggressive timeouts ran into oddities under heavier HTTP/3 use. Validate idle timeouts, header limits, and buffer sizes end‑to‑end (proxy → Kestrel → app).
EF Core provider mismatch. New EF Core 10 features often rely on provider updates that ship separately. Align provider versions with your database server capabilities before toggling anything in production.
Security posture drift. Major upgrades are a great time to re‑scan secrets, rotate credentials, and audit request pipelines. If you’re juggling other stacks too, see our React and Next.js security pieces—the habits in this React RCE playbook translate directly to disciplined patching on .NET.
Sample upgrade script (safe to copy)
• Verify SDKs: dotnet --list-sdks
• Create migration branch: git checkout -b upgrade/net10
• Update target frameworks: set <TargetFramework>net10.0</TargetFramework>
• Update packages: dotnet list package --outdated then bump to 10‑aligned versions
• Build and test: dotnet build -c Release, dotnet test -c Release
• Publish canary: dotnet publish -c Release --no-restore, deploy to a 1–5% pool
What to do next
• Kick off the 45‑day plan. Assign an engineering lead, publish the inventory, and open a migration epic today.
• Schedule a two‑hour spike. Prove you can compile and run your top‑risk service on net10.0 this week.
• Decide on AOT per service. Benchmark, don’t guess. Keep it opt‑in.
• Align tooling and costs. If you’re leaning into AI‑assisted dev in Visual Studio 2026, tune quotas and observability—start with our guidance on containing Copilot costs.
• Need a partner? If you want a seasoned crew to blueprint your migration and handle the heavy lifting, explore our modernization services. You can also see how we run similar zero‑drama upgrades in our Node.js 24 LTS playbook.
Zooming out
Upgrading platforms is about tempo and trust. With .NET 10 LTS already on its first servicing release, the window is perfect: tooling is stable, the patch cadence is moving, and you’ve got a clear runway before 2026 turns hectic. Run a tight play: inventory, parallelize, measure, and roll forward with confidence. Six weeks from today, you’ll be on a supported, faster foundation—and your future self will thank you.
If you want more hands‑on guides and incident‑tested runbooks, keep an eye on the ByBowu blog. We publish what we ship.
