Microsoft has released the .NET update for September 2025, and if you’re someone who associates “monthly update” with “security patches,” there’s a key difference this month.
At ByteHide, we’ve reviewed the official announcement to give you the precise summary you need. Unlike the typical “Patch Tuesday,” this month’s focus is 100% on stability. Let’s see what this means for your projects.
What’s New? Zero Security, All Quality.
The main headline is that for both .NET and .NET Framework, this month’s update contains no new security patches. The release is focused exclusively on quality and reliability improvements (“non-security fixes”).
This means the goal is to polish the ecosystem, fix bugs, and improve performance in specific areas, making the supported versions more stable.
The updated versions are:
| .NET Version | Release Notes | Installers and Binaries | Linux Packages |
|---|---|---|---|
| .NET 8.0.20 | Runtime 8.0.20 | 8.0.20 | 8.0.20 |
| .NET 9.0.9 | Runtime 9.0.9 | 9.0.9 | 9.0.9 |
The Aspnetcore changelogs for both versions have also been updated.
What About .NET Framework?
The same philosophy applies to the .NET Framework. The announcement confirms there are no security updates this month, but quality improvements have been released. To find the specific details about these enhancements, Microsoft directs us to the official .NET Framework release notes.
Our Recommendation: Should You Update?
Since this is not a security update, the urgency is lower, but the recommendation remains clear: yes, you should update.
Installing these versions ensures you are working on the most stable, bug-free foundation available. It’s good “code hygiene” that can prevent performance issues or unexpected behavior down the road. This is a low-risk update with long-term benefits.
Quick FAQ: September 2025 Edition
Is this a security update for .NET?
No. Microsoft’s official statement makes it clear that the September 2025 updates for .NET and .NET Framework do not contain any new security patches.
So, why should I install it?
To benefit from the latest bug fixes and stability improvements. These updates resolve issues reported by the community and enhance the overall reliability of the runtime, which can make your applications more robust.
Which .NET versions have been updated?
The versions that received these quality improvements are .NET 8.0.20 and .NET 9.0.9.
Will this update affect my existing code?
It is extremely unlikely. Servicing updates are designed to be fully backward-compatible and do not introduce breaking changes. Their sole purpose is to improve the existing implementation of the framework.
