Which .NET Version Should I Use Right Now?

⚡ Existing applications on .NET 9

Treat .NET 9 as a temporary stop, not a destination. It is fine if you knowingly chose STS, but you should already have a plan to move to .NET 10 well before 2026 ends.

🧯 Applications on .NET 6 or .NET 7

These versions are already out of support. Running out-of-support frameworks is not just a security concern. Over time, tooling, hosting providers, and third-party libraries quietly move on, and your upgrade becomes harder and more expensive. If possible, jump straight to .NET 10. If not, use .NET 8 as a short-term bridge.

🪟 .NET Framework applications

If you are on .NET Framework, your decision is different. For Windows-only legacy systems with heavy dependencies, staying put for now may be realistic. For anything that needs cloud deployment, containers, cross-platform support, or modern performance, you should plan a gradual migration to modern .NET.

🎯 A decision framework that actually works

• Is this a new app meant to live for years? Use .NET 10.

• Do you want the least maintenance and longest support? Use .NET 10 LTS.

• Are you blocked by dependencies or vendors? Use .NET 8 temporarily and plan your move to .NET 10.

• Are you intentionally upgrading every one to two years? Then .NET 9 can make sense.

🛠️ Locking your team to the right version

Check installed SDKs.

dotnet --list-sdks
dotnet --list-runtimes

Pin the SDK using global.json to avoid environment drift.

{"sdk": {
    "version": "10.0.100",
    "rollForward": "latestFeature"}}

Target the correct framework.

<PropertyGroup>
  <TargetFramework>net10.0</TargetFramework>
</PropertyGroup>

For shared libraries.

<PropertyGroup>
  <TargetFrameworks>net8.0;net10.0</TargetFrameworks>
</PropertyGroup>

🔄 A low-risk upgrade strategy

• Upgrade the SDK and build pipeline first without changing the target framework. This separates tooling issues from runtime issues.

• Update NuGet packages early because most upgrade problems come from outdated dependencies.

• Avoid mixing framework upgrades with large refactors so rollbacks stay cheap.

• Measure before and after. Startup time, memory usage, throughput, and latency should guide decisions, not assumptions.

⚠️ Common mistakes teams keep making

• Choosing STS for long-lived systems and forgetting to upgrade.

• Staying on unsupported versions because nothing is broken yet.

• Upgrading without pinning the SDK and wasting time debugging environment differences.

🧾 Final recommendation

If you want one boring, correct answer, use .NET 10.

It gives you the longest support window, aligns with Microsoft’s direction, and minimizes forced upgrades.

Use .NET 8 only as a short-term step if you are blocked.
Use .NET 9 only if you are disciplined about upgrading again.

❓ Top 5 FAQs: Choosing the Right .NET Version

1. Should I still start a new project on .NET 8?

Only if you have a hard dependency that does not yet support .NET 10. Otherwise, .NET 10 is the better long-term choice.

2. Is .NET 9 safe for production?

Yes, but only if you treat it as short-term. The risk is not stability, it is forgetting to upgrade later.

3. How often should I upgrade .NET in production apps?

Most teams should upgrade every LTS cycle, roughly every three years. STS requires a faster and more disciplined cadence.

4. Can I skip versions when upgrading .NET?

In most cases, yes. Many teams move directly from .NET 6 or 7 to .NET 10 as long as dependencies are compatible.

5. Does upgrading .NET automatically improve performance?

Often, but not magically. Real gains come when you upgrade, test, measure, and remove old workarounds that newer runtimes no longer need.