PostSharp 2026.0 Generally Available: Support for .NET 10, C# 14 and Extension Blocks

.NET 10 and C# 14

We’ve updated and tested PostSharp to fully support the .NET 10 SDK and C# 14 across all packages. You can now confidently use PostSharp with the latest .NET stack.

Extension Blocks Support

C# 14 introduces extension blocks as an alternative syntax for defining extension methods. This new language feature required careful consideration in PostSharp to ensure predictable behavior.

By default, multicast attributes now skip extension block members. This prevents aspects from being unintentionally applied to compiler-generated metadata associated with extension blocks.

For scenarios where you do want to target extension block members, we’ve added the AllowExtensionBlockMembers property to both MulticastAttribute and MulticastAttributeUsageAttribute. Setting this property to true enables your aspects to target extension block members explicitly.

Additionally, developers using IAspectProvider or IAdviceProvider interfaces can use the new ReflectionHelper.IsExtensionBlockMetadata utility method to identify compiler-generated metadata associated with extension blocks.

Updated Framework Baselines

We’ve raised the minimum supported frameworks to reflect the current .NET ecosystem:

• .NET Standard 2.0 (minimum)
• .NET Framework 4.7.0 (minimum)
• .NET 6.0 (minimum for .NET Core-based projects)

All pre-2017 target frameworks and obsolete .NET Core versions that have lost mainstream support have been removed. Please consult the breaking changes documentation for complete migration guidance.

Conclusion

PostSharp 2026.0 continues our commitment to keeping PostSharp compatible with the latest .NET releases. While our new feature development is focused on Metalama, we remain dedicated to ensuring that PostSharp users can stay current with the evolving .NET platform.

Happy meta-programming with PostSharp!