Move to .NET 10 LTS: What’s New, What Breaks, What Wins

.NET 10 LTS is officially out as of November 11, 2025, with three years of support. That means your next enterprise upgrade decision just got simpler: invest in a platform that won’t make you revisit the core runtime for a while. The headline upgrades are tangible—C# 14 quality‑of‑life features, ASP.NET Core 10 security and diagnostics boosts, EF Core 10’s vector and JSON type support, performance across the stack, and day‑one support in Visual Studio 2026. If you’ve been hanging on .NET 8 or sampling .NET 9, this is the release to standardize on.

Why .NET 10 LTS now?

Start with the basics: .NET’s cadence is annual in November. Even‑numbered versions are LTS (three‑year support), odd‑numbered are STS. Earlier this fall, Microsoft extended STS from 18 to 24 months, so .NET 9 and .NET 8 both reach end of support on November 10, 2026. .NET 10 LTS runs through November 2028, giving you a stable base for multi‑year product roadmaps.

Practically, this means you can upgrade once, then focus your energy on features and customer outcomes instead of runtime churn. For teams working under compliance or long procurement cycles, that’s the difference between chasing patch notes and shipping.

What’s actually new in .NET 10 LTS

Language: C# 14 makes daily code cleaner

C# 14 brings extension members so you can add properties and operators to existing types without weird patterns; field‑backed properties so you can start from auto‑props and inject minimal logic cleanly; and better span/array interop that removes ceremony and unlocks JIT optimizations. The impact isn’t academic—you’ll see smaller diffs, fewer allocations, and simpler APIs in your own code and the BCL you consume.

Developer takeaway: budget a half‑day tech talk to align on new idioms (extension members, the field contextual keyword) so your reviewers don’t fight over style.

Runtime and libraries: performance and safety

Expect sensible defaults that trend safer and faster. Memory management sees tightened loops and a smarter pool that can return idle buffers to the OS. JSON serialization defaults lean more secure and throughput‑friendly. Hardware acceleration expands on x64 and Arm64, and NativeAOT’s output gets leaner. If you ship services at scale, these are boring, valuable wins.

ASP.NET Core 10: secure auth, richer diagnostics, real‑time hooks

There’s a lot for web teams. Passkey support lands in ASP.NET Core Identity and the Blazor template, letting you roll passwordless sign‑in without bolting on fragile glue code. Diagnostics get a lift with new built‑in metrics across request pipelines, auth, Identity, Blazor, and the memory pool. Minimal APIs pick up niceties, and TypedResults.ServerSentEvents makes it straightforward to stream updates over SSE when WebSockets would be overkill.

Developer takeaway: enable the new metrics, wire them to your observability stack, and add optional passkeys alongside your existing flows. It’s a practical security upgrade users actually feel.

EF Core 10: vectors and native JSON

EF Core 10 adds first‑class support for the new vector data type and its distance functions in Azure SQL and SQL Server 2025, plus a true json column type. That means semantic search and hybrid retrieval patterns without jumping out to a separate vector store, and JSON documents that are stored efficiently and validated at the database level.

Developer takeaway: you’ll need Azure SQL or SQL Server 2025 compatibility for vectors and the new JSON type. If you’re on older SQL versions, EF will still work—just without those specific wins.

.NET MAUI: quality and build‑time XAML

.NET MAUI in .NET 10 continues the stabilization track: compile‑time XAML generation surfaces errors earlier and speeds startup, platform bindings update to Android 16 and iOS 26, and there’s tighter hooks for web views (including request interception) and media capture. You can also opt into Aspire defaults in the new template to get OpenTelemetry wiring for free.

Product note: MAUI, like some workloads, ships out‑of‑band and follows its own support lifecycle. Keep that in mind if you’re still on historical versions; plan your upgrade path intentionally.

Tooling: Visual Studio 2026 and better CLI ergonomics

Visual Studio 2026 ships alongside .NET 10 with built‑in C# 14 support, deeper test and profiler flows, and improved Razor and Aspire experiences. On the command line, the SDK adds smarter dotnet tool behaviors and better introspection. If your team spans Windows, macOS, and Linux, these quality‑of‑life bumps show up in day‑to‑day dev speed.

Will .NET 10 LTS break my app?

Most teams moving from .NET 8 will see minimal breakage, especially if you’re current on monthly patches. Still, there are sharp edges worth checking:

• Out‑of‑band workloads: MAUI, some mobile toolchains, and IDE integrations have independent lifecycles. Verify their versions against the .NET 10 SDK you install.
• EF provider versions: update your provider (SQL Server, Npgsql, etc.) to versions that explicitly support EF Core 10 before you flip frameworks.
• Providers and middleware: if you rely on libraries that hook into low‑level pipeline internals, test those code paths under load. Diagnostics and memory changes can surface timing issues.
• Container images: moving to .NET 10 base images means new CA cert bundles and root images; rebuild and scan images, then smoke test in your staging cluster.

Should you skip .NET 9 and jump to .NET 10 LTS?

Yes, if you manage production workloads with multi‑year horizons. With STS now 24 months, .NET 9 remains supported through November 2026, but you’d be upgrading again sooner. Standardize on .NET 10 LTS and put your effort into product work. If you’re mid‑project on .NET 9, it’s sane to ship on 9 this quarter and plan a short hop to 10 early next year.

C# 14 in practice: where the wins appear

Three places you’ll feel it:

• Extension members reduce adapter noise. You can enrich BCL and domain types directly, which makes APIs more discoverable.
• Field‑backed properties give you a gentle migration path from auto‑props to custom accessors—no backing field ceremony, fewer bugs.
• Span interop makes performance‑sensitive code read like ordinary code, without a trail of temporary allocations and conversions.

Set a team convention: adopt these in new code and when refactoring hot paths. Avoid sweeping rewrites just for aesthetics.

ASP.NET Core 10: pragmatic upgrades for web teams

Here’s the short list we’re rolling out for clients:

• Passkeys: add optional passwordless auth to your login flows. Users get fewer phishing risks, and your support queue gets fewer reset tickets.
• Metrics on by default: wire the new counters to your observability backend and add SLOs for request latency, auth errors, and memory pool pressure.
• SSE for small real‑time features: use TypedResults.ServerSentEvents for dashboards and status feeds where WebSockets are overkill.
• ProblemDetails normalization: unify error payloads across minimal APIs and MVC so clients stop special‑casing failures.

If you’re exploring the broader .NET ecosystem change, our 30‑day upgrade game plan in Ship Sooner on .NET 10 LTS pairs well with these ASP.NET Core moves.

EF Core 10 and SQL 2025: when to adopt vectors and JSON

If you’re building search experiences, vector columns are compelling. You can compute cosine distance over embeddings natively in the database and combine it with relational filters in a single query. Start with a narrow use case—e.g., semantic FAQ search—before you re‑platform your entire search strategy.

For operational data, the json column type is a safer way to store schemaless bits than a big NVARCHAR. You get validation and better space efficiency. Map complex owned types or primitive collections without gymnastics, and keep your relational model sane.

MAUI reality check

For mobile teams, the .NET 10 story is about quality improvements and platform currency. The build‑time XAML generator and updated Android/iOS bindings are the highlights. But remember: MAUI’s cadence is not the same as the core runtime. Align your SDKs, workloads, and IDE versions in lockstep, and keep an eye on your supported OS versions in the stores.

The 3×3 LTS Migration Grid

Here’s a simple framework we use to plan upgrades without chaos. Score each row Green/Yellow/Red, then pick your path.

1) Codebase fit

Modernity: Are you on .NET 8 or 9 with minimal custom GC settings? Interop: Any heavy P/Invoke, unsafe code, or legacy config that may be sensitive to runtime changes? Testing: Do you have reliable integration tests and load tests?

2) Dependency readiness

EF provider: Are your database providers and migrations on versions that support EF Core 10? Libraries: Do auth, caching, messaging, and observability libraries list .NET 10 support? Containers: Are base images available, scanned, and pinned by digest?

3) Operations maturity

Observability: Can you ingest new ASP.NET Core metrics and OpenTelemetry signals? Security: Can you roll passkeys and rotate keys/certs across environments? Release: Can you canary and roll back within minutes?

Next, choose a track: Green scores go straight to .NET 10 LTS in a single sprint; Yellow split into two sprints (framework first, feature toggles second); Red carve out a pilot service, fix gaps, then scale.

Week‑one checklist

• Lock toolchain versions in CI: .NET 10 SDK, matching workloads, and container base images.
• Upgrade to C# 14 in a feature branch; run analyzers and fix new warnings in hot paths only.
• Update EF provider and regenerate migrations; validate on a SQL 2025/Azure SQL clone if you plan vector/JSON adoption.
• Enable ASP.NET Core’s new metrics and trace a typical request flow end‑to‑end in staging.
• Add passkeys as an optional auth method; don’t rip out passwords/SAML/OIDC on day one.
• Rebuild and scan your Docker images; run smoke tests on staging k8s with canary traffic.
• Load‑test before and after the upgrade; watch GC, memory pool behavior, and tail latencies.
• Document rollbacks: SDK pin, base image revert, env var toggles, and feature flags.
• Schedule a production pilot on a low‑risk service with clear SLOs.
• Plan the follow‑up sprint for refactors that take advantage of C# 14 features.

People also ask

Is .NET 10 LTS stable enough for production?

Yes. It’s the supported baseline through late 2028. If you’re current on .NET 8 patches, the jump is a small diff with measurable perf and security upside.

Do I have to use Visual Studio 2026 to target .NET 10?

No, but it’s the smoothest route on Windows—with C# 14, Razor, and Aspire experiences baked in. VS Code with the latest C# Dev Kit also works well. Pin your SDKs in global.json regardless.

Will .NET 10 break my NuGet packages?

Most mainstream libraries updated during the release candidates. Still, audit your top 20 packages for framework and EF Core 10 compatibility. Update, then run integration tests.

What about Docker and cloud images?

Refresh to the .NET 10 base images, rebuild with your SBOM/supply‑chain scans, and retune resource requests. NativeAOT images often cut cold start and memory—measure in your environment.

Zooming out: the strategy call

You’ve got two tracks. If you’re an enterprise with dozens of services, standardize on .NET 10 LTS now to unify toolchains and training. If you’re a startup shipping weekly, adopt .NET 10 LTS in the services that benefit most—APIs under load, anything touching auth, or apps that will exploit EF’s vector/JSON features—then roll across the fleet. Either way, make the move deliberate, observable, and reversible.

For a structured path, our .NET 10 LTS production upgrade playbook dives deeper on branch strategy, testing gates, and rollback planning. And if you’d rather ship features than run migrations, our team can help—see modernization and platform services or book an assessment.

What to do next

• Create a global.json to pin the .NET 10 SDK and lock workloads in CI.
• Upgrade one service this week. Enable passkeys and the new metrics; measure before/after.
• Plan EF Core 10’s vector/JSON adoption where it moves a KPI, not everywhere.
• Set a team “C# 14 conventions” doc and update analyzers to match.
• Schedule your fleet rollout. Use canaries and SLOs, not big‑bang cutovers.

If you want a condensed blueprint, grab our 30‑day .NET 10 LTS playbook and share it with your leads. We’ve helped teams move fast without breaking production—see a few wins in our client portfolio and ping us when you’re ready.