We’re excited to announce the release of PostSharp 6.1 RTM which is now available for download from our website and NuGet

PostSharp 6.1 significantly improves debugging experience and allows you to implement logging for distributed systems. 

The feature list includes:

  • Improved debugging experience, especially of async methods with aspects
  • Semantic logging and statistical processing of log records
  • Distributed logging: it became easier to make sense out of centralized logs
  • Sampled logging: select which details to log and which to ignore
  • Improvements in support for C# 7.3, .NET Standard and other fixes

For a detailed description of all new features, please read the release candidate announcement.

We hope you'll enjoy the improvements!

Happy PostSharping,



I’m happy to announce we’ve just published PostSharp 6.1 RC, available for download on nuget.org (make sure to enable pre-release packages) and on our website .

This release focuses on two areas: we improved the debugging experience, and we took our logging API up to the expectations of a cloud-based, AI-enabled world.

Improved Debugging Experience

PostSharp 6.1 includes a major refactoring of our add-in to the Visual Studio debugger. This add-in makes sure the debugging experience (such as pressing F10 or F11) is natural when aspects are woven into hand-written code. We’ve been working on this feature for more than a year, and we’re excited to finally roll it out.

PostSharp 6.1 fixes most known issues in the debugging experience with a special focus on the debugging of async methods. In previous versions, debugging an aspected async method could be pretty challenging. It now behaves very smoothly.

This feature was a major engineering effort and it has disappointingly little visibility. If we’ve done our job properly, you will not notice any difference when debugging code with or without an aspect. We’re very proud of this achievement and happy it’s finally out.

Semantic Logging

In the past, the primary consumers of logs were human beings. Times are changing. More and more often, logs are stored in centralized and structured servers like Elasticsearch or Application Insights, and statistical processing becomes more important than human readability. And statistical processing, as you know, starts with bucketizing. You want to find the most frequent warning with its most frequent parameters. The problem is, how do you bucketize a human-readable string?

Structured logging is a long step in the right direction because it makes it easier to filter on parameters, but it still based on human-readable strings, and they are still difficult to bucketize.

Enter semantic logging. Contrarily to structured logs, semantic logs are not primarily designed to be read by humans. Each message has a name and a list of name-value pairs. That’s it. Unlike structured logs, it is extremely easy to bucketize semantic logs.

Semantic logging has been with .NET since 2014, although largely ignored. However, I believe that the current cloud & AI trends warrant a shift of mindset, and we’ve implemented support for that in PostSharp 6.1.

For more details, see Writing semantic messages for easy statistical processing in the online documentation.

Distributed Logging

As more and more customers are moving to microservices, distributed logging is becoming increasingly important every day. How to get a consistent trace for the processing of a request whose execution spans several machines? Several practices and specifications like OpenTracing or the HTTP Correlation Protocol are emerging, and logging frameworks need to evolve to support the new concepts.

PostSharp 6.1 brings two improvements for distributed logging:

  • Hierarchical Ids: we can generate ids that let you easily select all records of a distributed request with a wildcard query such as Properties.EventId: "|2ceff3ef47.a2.*", and sort them alphabetically for logical ordering. The generated ids comply to the Hierarchical Request-Id specification .
  • You can now attach properties to custom activities and custom log messages, and mark these properties as cross-process (this implements the Tag and Baggage concepts of OpenTracing).

For more details, see Implementing Logging for a Distributed System in the online documentation.

Sampled Logging

PostSharp Logging makes it so easy to add logging to your application that you can easily end up capturing gigabytes of data every minute. As it goes, most of this data won't ever be useful, but you still need to pay for storage and bandwidth. The ability to trace an application at a high level of detail is very useful, but it is important to be able to select when you want to log. This is especially relevant in web applications.

Starting from PostSharp 6.1, you can select which requests you want to log, and which ones you want to ignore.

For more details, see Choosing Which Requests to Log in the documentation.


In PostSharp 6.1, we focused on two areas: the debugging experience (especially async methods) and logging of distributed applications.

Other improvements include support for C# 7.3, filling gaps in .NET Standard support, and a few other features you will find in What's New in PostSharp 6.1 .

As always at PostSharp, when we say RC, we really mean it: complete tests and documentation, API freeze, backward compatibility, and most importantly, zero known important bugs. It is ready to be tested in your projects, and you can expect an RTM in April.

Happy PostSharping!


We regret to inform you that the upcoming Visual Studio 2017 Update 8 (15.8) will introduce a change that will break PostSharp NuGet packages with versions 5.0.0-5.0.52 and 6.0.0-6.0.17. The issue has been addressed in 5.0.53 and 6.0.18. 

The cause of the problem is our use of the developmentDependency  flag in our *.nuspec files. Our interpretation of the documentation was apparently incorrect from the beginning but the flag was not properly implemented by Visual Studio, and therefore everything worked perfectly. Now the team at Microsoft decided to implement the flag "properly" at the cost of breaking previous packages, including PostSharp. We discovered the issue while testing the preview of VS 15.8 and reported it to Microsoft but they decided to do the breaking change anyway.

The problem affects projects using the new CPS format with <PackageReference> instead of packages.config. The problem will occur when you will add a PostSharp package to your project. Existing projects that already have a reference to the packages are not affected.

If you are affected by the issue, you have two options:

  • Use PostSharp version 5.0.53 or 6.0.18 if you have an active support subscription or use PostSharp Essentials.
  • Otherwise, you can manually edit the NuGet packages you depend on by unzipping them, removing the developmentDependency flag from the nuspec file, and rezipping them.

This is not the first time that Microsoft does breaking changes and we understand this is the price to pay for the faster release pace we've enjoyed during the last months.

Happy PostSharping nevertheless!



EDIT: Fixed an incorrect information that only projects targeting .NET Core or .NET Standard are affected. Projects targeting .NET Framework may be affected too if they have been converted to PackageReference.