New Swashbuckle release with .NET 8 support

swashbuckle nuget portal page with 6.6.1 release

Swashbuckle.AspNetCore v6.6.1 was released recently, bringing native .NET 8 support and other improvements, so it’s time to update if you experienced related problems before.

Why upgrade?

If you are using .NET 8 with an older version of Swashbuckle nuget package you may get an error similar to these:

You must install or update .NET to run this application.
App: C:\Users\username\.nuget\packages\swashbuckle.aspnetcore.cli\6.5.0\tools\net7.0\any\dotnet-swagger.dll
Architecture: x64
Framework: 'Microsoft.NETCore.App', version '7.0.0' (x64)


Error MSB3073 The command "dotnet swagger tofile --output swagger.json YouApp.dll v1 " exited with code -532462766.

or even something like

Unhandled exception. System. IO. FileLoadException: Could not load file or assembly 'System. Runtime, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The located assembly's manifest definition does not match the assembly reference. (0x80131040)

Even though there are some workarounds to make the older packages work with .NET 8, updating Swashbuckle packages is the easiest way to handle this.

How to upgrade Swashbuckle NuGet packages?

For projects referencing Swashbuckle package, you can use Visual Studio NuGet Package Manager to update them manually, or by executing this dotnet CLI command from the command line (make sure to update each Swashbuckle.* package you reference!):

dotnet add package Swashbuckle.AspNetCore

Alternatively, we can also update the packages using this PowerShell command from the Package Manager Console in VS:

Update-Package Swashbuckle.AspNetCore

Or if you want to update all packages, just:


How to upgrade Swashbuckle.AspNetCore.Cli?

If you are using Swashbuckle.AspNetCore.Cli dotnet tool for build-time swagger file generation or other purposes, you can update it by running this dotnet tool command:

dotnet tool install -g Swashbuckle.AspNetCore.Cli

This will update (install) the latest version of Swashbuckle.AspNetCore.Cli globally.

However, for .NET 6+ projects, it’s recommended to use local tools defined in the tool manifest (dotnet-tools.json file in .config folder). To update the local tool you can run this command in your root solution folder:

dotnet tool install Swashbuckle.AspNetCore.Cli

This command will upgrade the tool to the latest available version and change the dotnet-tools.json accordingly:

  "version": 1,
  "isRoot": true,
  "tools": {
    "swashbuckle.aspnetcore.cli": {
      "version": "6.6.2",
      "commands": ["swagger"]

If you don’t have dotnet-tools.json manifest, you can create one by executing this command in the root solution folder:

dotnet new tool-manifest


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