This article is part of a series on Migrating from .NET Framework to .NET, also available as a chapter in our free, downloadable eBook

.NET 10 is here, and Microsoft’s .NET support policies are still confusing. There’s .NET Framework, .NET Core, .NET Standard, and now the current .NET (.NET 5 to .NET 9). All of them seem to have different life cycles and different end-of-support dates.

You’ve probably heard of “Long Term Support (LTS)“, which was introduced back in 2020 with .NET 5. But the exact duration of “long term” isn’t so obvious. Nor is “Standard Term Support (STS)“, which most (including me) thought meant “Short-Term”.

In this article, we’ll look at Microsoft’s .NET support policies, and hopefully clear up how long your version of .NET is really supported for, allowing you to better plan for the future.

So… How Long-Term is Long-Term Support (LTS) Exactly?

As it turns out, not so long! Long Term Support (LTS) refers to Microsoft’s support policies for it’s .NET releases. Microsoft defined a new release cadence starting in .NET 5 that applies to all versions going forward. Here’s how it works:

• Even numbered releases (.NET 6, 8, etc.) have “Long Term Support” (LTS) of up to 3 years after release

• Odd numbered releases (.NET 9 etc.) have “Standard Term Support” (STS) of up to 2 years after release. This used to be only 18 months until .NET 7, however Microsoft announced in 2025 that they would be extending this to 2 years from .NET 9 onward.

The irony is that “long-term” isn’t really that long at all, especially compared to .NET Framework 3.5. That’s supported until 2029! And then there’s .NET Framework 4.8, which has support tied to the operating system – and there’s no foreseeable date it will be unsupported.

So, while .NET 10 has “Long Term Support”, the reality is .NET Framework will be supported far beyond it, and even .NET 11 or .NET 12!

Support Policies Vary by .NET Platform

LTS and STS only refer to .NET, and for other versions the support policies will depend on the .NET platform that you’re using. Here’s a quick rundown.

.NET Framework was introduced by Microsoft in 2002 and has had various releases over time from 1.0 to 4.8. Support varies, and most versions are already out of support, however:

• .NET Framework 3.5: Will be supported until April 2029
• .NET Framework 4.8: Support is now tied to the operating system it’s installed on, and will be supported indefinitely, well beyond the next ten years

.NET Core was introduced as an evolution of .NET Framework. It had various releases, from 1.0 to 3.1. It has now reached end of support, with .NET Core 3.1 support having concluded on December 13, 2022.

.NET Standard: .NET Standard served as a compatibility bridge between .NET Framework and .NET. It’s last version was 2.1, however, support is now tied to future versions of .NET, supported for as long as they are.

Xamarin: Xamarin revolutionized mobile app development by enabling cross-platform applications using C# code sharing. Support for this will end on May 1, 2024. Users of this are advised to upgrade to .NET MAUI

The current .NET series is Microsoft’s latest series of .NET versions, starting with .NET 5 in 2020. Microsoft has a new release cadence, and support policy in line with this:

• STS (standard term support) is 2 years for odd-numbered versions (1 year after a subsequent STS or LTS release)
• LTS (long term support) is 3 years for even-numbered versions

So… is My .NET Version Supported?

Regarding support life cycles, this table illustrates that despite Microsoft designating certain .NET versions as LTS, most are relatively close to the end of their support, with several versions of .NET Framework supported far beyond this, despite being released years earlier.

What if my .NET is out of support?

If a version has reached it’s out-of-support date, this means that Microsoft no longer provides fixes, updates, or online technical assistance. This means there are:

• Security Risks: Without ongoing security updates, applications become more vulnerable.
• Compatibility Concerns: Versions may not work seamlessly with newer operating systems, hardware, and third-party software.
• No Technical Assistance: Microsoft will not offer official technical support for issues related to the out-of-support version.
• Performance and Stability: Lack of updates can lead to performance degradation and stability issues over time.
• New Features: New features and enhancements introduced in later versions of the framework won’t be available.

So while your unsupported .NET software will not suddenly stop working, it’s a good idea to upgrade.

What Actions Should I Take?

• If you are on .NET Framework there is no immediate urgency to migrate
• If you are on .NET Core your system is no longer supported and you should migrate to .NET as soon as possible
• If you are on .NET you need to keep in mind when your End of Service date is for your version, and plan updates accordingly

Migrating from .NET Framework to .NET? Don’t let this article slip away —save it for future reference! It’s a chapter in our free eBook, the .NET Migration Guide. From migration strategies to just learning what has been deprecated and what hasn’t, we’ve outlined the key information you’ll need to know for .NET migration in your organization! Download your free copy today!