NServiceBus.AzureFunctions.Worker.ServiceBus 4.2.0 – Minor release available

Hi everyone,

We’ve just released NServiceBus.AzureFunctions.Worker.ServiceBus 4.2.0.

NOTE: Version 4.2.1 has already been released with a fix for an Outbox bug unrelated to this release.


  • #302 Prevent the use of NSB configuration APIs which are not applicable to serverless environments
  • #301 Add support for installers
  • #264 Handle `UseTransport` gracefully

Fixed bugs

  • #220 Using SendOnly throws a KeyNotFoundException with Main as a key

How to know if you are affected

You are affected if you are trying to create a Send-only endpoint in an Azure Functions (isolated worker) host.


When a SendOnly endpoint is created, a KeyNotFoundException is thrown regarding the Main key on the first message operation.

When to upgrade

You should upgrade during your next maintenance window.

Where to get it

You can install NServiceBus.AzureFunctions.Worker.ServiceBus 4.2.0 from NuGet.

With thanks,
The team in Particular

Please read our release policy for more details.