akkadotnet/akka.net 1.5.59

Akka.NET v1.5.59

on GitHub

1.5.59 January 27th, 2026

Akka.NET v1.5.59 is a maintenance release with critical bug fixes and new features for observability.

Critical Bug Fixes

• Fix MergeSeen to filter Seen against current Members - Fixes issue #8009. Resolves a cluster gossip serialization failure that could occur with the error "Unknown address in cluster message" when the Seen table contained addresses of members that had already left the cluster.

Bug Fixes

• Fix logger initialization continuation race in LoggingBus - Fixes a race condition during logger initialization that could cause logging failures during actor system startup.
• Fix Inbox.AwaitResult throwing AggregateException instead of TimeoutException - Inbox.AwaitResult now correctly throws TimeoutException when a timeout occurs, rather than wrapping it in an AggregateException.
• Fix DeferAsync async handler nesting bug in CommandAsync - Fixes issue #7998. Resolves an issue where DeferAsync with an async handler would throw "RunTask calls cannot be nested" when called from CommandAsync.
• Fix AwaitAssertAsync logic causing premature timeout - Fixes AwaitAssertAsync in Akka.TestKit to correctly wait for the full timeout duration before failing assertions.

New Features

• Add ActivityContext capture to LogEvent for trace correlation - Log events now automatically capture the current System.Diagnostics.ActivityContext when created, enabling correlation between Akka.NET logs and distributed traces in observability platforms like OpenTelemetry, Application Insights, and Jaeger.
• Add BroadcastHub startAfterNrOfConsumers parameter - Fixes issue #8017. Port from Apache Pekko - adds a startAfterNrOfConsumers parameter to BroadcastHub.Sink<T>() that delays broadcasting until the specified number of consumers have subscribed:

  // Wait for 3 consumers before starting to broadcast
  var sink = BroadcastHub.Sink<int>(startAfterNrOfConsumers: 3, bufferSize: 256);

Improvements

• CoordinatedShutdown: clearly log the reason why we're exiting - CoordinatedShutdown now logs the specific reason for shutdown at INFO level, making it easier to diagnose why an actor system terminated.

To see the full set of changes in Akka.NET v1.5.59, click here.

Changes:

• 85889e2 Update version to 1.5.59 in Directory.Build.props
• bbb7087 Add release notes for Akka.NET v1.5.59 [ #8011 ]
• f7b7758 Update API approval files for 1.5.59 backport
• b1d6d10 Fix MergeSeen to filter Seen against current Members (#8009) (#8011)
• da692cb Add ActivityContext capture to LogEvent for trace correlation (#7995) [ #6855 ]
• 1ada635 Fix logger initialization continuation race in LoggingBus (#8006)
• 5284e13 Add BroadcastHub startAfterNrOfConsumers parameter (#8017) (#8018) [ #275, #1841 ]
• 99b00c5 Fix Inbox.AwaitResult throwing AggregateException instead of TimeoutException (#8005)
• 7e18fb8 Fix DeferAsync async handler nesting bug in CommandAsync (#7998) (#7999)
• bc85915 CoordinatedShutdown: clearly log the reason why we're exiting (#7988)