akkadotnet/akka.net 1.5.62

akka.net v1.5.62

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1.5.62 March 3rd, 2026

Akka.NET v1.5.62 is a maintenance release with an important bug fix for logging stability when using third-party logging providers.

Bug Fixes

• Fix: catch FormatException in log formatters to prevent third-party logger crashes - Fixes a crash caused by malformed log format strings.

1 contributor since release 1.5.61

To see the full set of changes in Akka.NET v1.5.62, click here.

1.5.61 February 26th, 2026

Akka.NET v1.5.61 is a maintenance release with important bug fixes for Akka.Cluster.Sharding, Akka.Cluster, and Akka.Core.

Akka.Cluster.Sharding Bug Fixes

• Port Pekko ShardStopped handler + handoff safety net - Fixes issue #7500. Resolves a critical issue where shards could fail to hand off indefinitely during scale-up events.
• Fix Shard remember-entities flag mismatch causing entity restart failures - Fixes a bug where the Entities class was initialized with the wrong RememberEntities flag.
• Correct self-comparison in ShardCoordinator ResendShardHost handler - Fixes a bug where the ResendShardHost handler compared a region variable to itself instead of comparing against the message's region.

Akka.Cluster Bug Fixes

• VectorClock inequality fixes - Fixes the != operator which incorrectly delegated to IsConcurrentWith instead of being the logical negation of ==, and fixes the < operator to correctly exclude the equal case.
• Correct format index in 3-arg LogInfo overload - Fixes a logging bug where the 3-arg LogInfo overload used the wrong format index.

Bug Fixes

• Fix wrong randomFactor argument type on RetrySupport.Retry() - Fixes issue #8059. Changes the randomFactor parameter type from int to double to match the expected behavior for jitter calculations.
• AppVersion.CompareTo missing else if breaks comparison symmetry - Fixes a bug where release versions appeared less than their pre-release counterparts.
• Remove stray dollar signs from interpolated strings - Fixes three string interpolation bugs in output in ClusterHeartbeat, ShardRegion, and SinkRefImpl.

Improvements

• Downgrade VirtualPathContainer RemoveChild log from Warning to Debug - Fixes issue #8037. Eliminates noisy warnings during high-load Ask operations.

4 contributors since release 1.5.60

To see the full set of changes in Akka.NET v1.5.61, click here.

1.5.60 February 9th, 2026

Akka.NET v1.5.60 is a maintenance release with a bug fix and a new feature for structured logging.

Bug Fixes

• Fix TestActor initialization race in parallel test startup - Fixes a race condition where TestActor could receive messages before its initialization was complete when tests were run in parallel, causing intermittent test failures.

New Features

• Add logging context enrichment and scopes - Fixes issue #7535. Adds WithContext() and BeginScope() extension methods to ILoggingAdapter for structured logging context enrichment. Context properties are automatically included in log output and forwarded to downstream logging providers like Serilog and NLog. See documentation.

  var log = Logging.GetLogger(Sys, "example");
  
  // Enrich a logger with additional structured context
  var enrichedLog = log
      .WithContext("Tenant", "foo")
      .WithContext("Partition", 12);
  
  enrichedLog.Info("Processing {Offset}", 42);
  // Output: [INFO][...][akka://sys/user/a][Tenant=foo][Partition=12] Processing 42
  
  // Create a temporary logging scope
  using (var scope = log.BeginScope("RequestId", "REQ-123"))
  {
      scope.Log.Info("Handling request {RequestId}", "REQ-123");
  }

To see the full set of changes in Akka.NET v1.5.60, click here.

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.

1.5.58 January 8th, 2026

Akka.NET v1.5.58 is a maintenance release with important bug fixes and performance improvements.

.NET 10 Compatibility Fix

• Fix .NET 10 CLR shutdown hook breaking change - Resolves an issue where the CLR shutdown hook behavior changed in .NET 10, ensuring graceful actor system termination works correctly.

Bug Fixes

• Fix TcpListener to not stop accepting connections on transient accept errors - The TcpListener now properly handles transient socket accept errors without stopping to accept further connections.
• Fix race condition in cluster sharding when entity constructor fails - Resolves a race condition that could occur when an entity actor's constructor throws an exception.
• Fix race condition in QueueSink causing async enumerable timeout - Fixes a race condition in QueueSink that could cause timeouts when using async enumerables.
• Make RemotingTerminator non-FSM to avoid racy FSM log init - Fixes potential race conditions during actor system shutdown logging.

Performance Improvements

• LogMessage GetProperties without FrozenDictionary - Improves semantic logging performance by avoiding FrozenDictionary allocations in hot paths.
• Skip parsing PropertyNames when empty Parameters - Additional logging optimization that skips unnecessary parsing when log messages have no parameters.

New Features

• Akka.TestKit: configurable expect-no-message-default value - Fixes issue #6675. You can now configure the default timeout for ExpectNoMsg() via HOCON:

  akka.test.expect-no-message-default = 100ms

6 contributors since release 1.5.57

1.5.57 December 11th, 2025

Akka.NET v1.5.57 is a minor release containing significant new features for Akka.Persistence and structured/semantic logging.

Akka.Persistence Completion Callbacks and Async Handler Support

• Persistence completion callbacks via Defer - simplified alternative - This release adds completion callback and async handler support to Persist, PersistAsync, PersistAll, and PersistAllAsync methods in Akka.Persistence. Key improvements include:
  • Async Handler Support: All persist methods now support Func<TEvent, Task> handlers for async event processing
  • Completion Callbacks: PersistAll and PersistAllAsync now accept optional completion callbacks (both sync Action and async Func<Task>) that execute after all events are persisted and handled
  • Ordering Guarantees: Completion callbacks use Defer/DeferAsync internally to maintain strict ordering guarantees
  • Zero Breaking Changes: All new APIs are additive overloads

Persistence Code Examples:

// Async handler support - process events asynchronously
Persist(new OrderPlaced(orderId), async evt =>
{
    await _orderService.ProcessOrderAsync(evt);
});

// PersistAll with completion callback - know when all events are done
PersistAll(orderEvents, evt =>
{
    _state.Apply(evt);
}, onComplete: () =>
{
    // All events persisted and handlers executed
    _logger.Info("Order batch completed");
    Sender.Tell(new BatchComplete());
});

// PersistAll with async handler AND async completion callback
PersistAll(events,
    handler: async evt => await ProcessEventAsync(evt),
    onCompleteAsync: async () =>
    {
        await NotifyCompletionAsync();
        Sender.Tell(Done.Instance);
    });

// PersistAllAsync with completion - allows commands between handlers
PersistAllAsync(largeEventBatch,
    handler: evt => _state.Apply(evt),
    onComplete: () => Sender.Tell(new BatchProcessed()));

The implementation maintains Akka.Persistence's strict ordering guarantees by using Defer/DeferAsync for completion callbacks, ensuring they execute in order even when called with empty event collections. The new async handler invocations (IAsyncHandlerInvocation) are processed via RunTask to preserve the actor's single-threaded execution model.

Native Semantic Logging Support

• Add native semantic logging support with property extraction - Fixes issue #7932. This release adds comprehensive structured logging support to Akka.NET with both positional ({0}) and named ({PropertyName}) message template parsing, enabling seamless integration with modern logging frameworks like Serilog, NLog, and Microsoft.Extensions.Logging. Key capabilities include:
  • New LogMessage.PropertyNames and GetProperties() APIs for property extraction
  • SemanticLogMessageFormatter as the new default formatter
  • Performance optimized with 75% allocation reduction compared to the previous implementation
  • Zero new dependencies and fully backward compatible
  • EventFilter support for semantic templates in unit tests

1 contributor since release 1.5.56

To see the full set of changes in Akka.NET v1.5.57, click here:

• 1.5.57-beta1 milestone
• 1.5.57-beta2 milestone

1.5.57-beta2 December 2nd, 2025

Akka.NET v1.5.57-beta2 is a beta release containing significant new APIs for Akka.Persistence that add completion callbacks and async handler support.

New Features:

• Persistence completion callbacks via Defer - simplified alternative - This release adds completion callback and async handler support to Persist, PersistAsync, PersistAll, and PersistAllAsync methods in Akka.Persistence. Key improvements include:
  • Async Handler Support: All persist methods now support Func<TEvent, Task> handlers for async event processing
  • Completion Callbacks: PersistAll and PersistAllAsync now accept optional completion callbacks (both sync Action and async Func<Task>) that execute after all events are persisted and handled
  • Ordering Guarantees: Completion callbacks use Defer/DeferAsync internally to maintain strict ordering guarantees
  • Zero Breaking Changes: All new APIs are additive overloads

Code Examples:

// Async handler support - process events asynchronously
Persist(new OrderPlaced(orderId), async evt =>
{
    await _orderService.ProcessOrderAsync(evt);
});

// PersistAll with completion callback - know when all events are done
PersistAll(orderEvents, evt =>
{
    _state.Apply(evt);
}, onComplete: () =>
{
    // All events persisted and handlers executed
    _logger.Info("Order batch completed");
    Sender.Tell(new BatchComplete());
});

// PersistAll with async handler AND async completion callback
PersistAll(events,
    handler: async evt => await ProcessEventAsync(evt),
    onCompleteAsync: async () =>
    {
        await NotifyCompletionAsync();
        Sender.Tell(Done.Instance);
    });

// PersistAllAsync with completion - allows commands between handlers
PersistAllAsync(largeEventBatch,
    handler: evt => _state.Apply(evt),
    onComplete: () => Sender.Tell(new BatchProcessed()));

Technical Details:

The implementation maintains Akka.Persistence's strict ordering guarantees by using Defer/DeferAsync for completion callbacks, ensuring they execute in order even when called with empty event collections. The new async handler invocations (IAsyncHandlerInvocation) are processed via RunTask to preserve the actor's single-threaded execution model.

1 contributor since release 1.5.57-beta1

To see the full set of changes in Akka.NET v1.5.57-beta2, click here

1.5.57-beta1 December 2nd, 2025

Akka.NET v1.5.57-beta1 is a beta release containing a significant new feature for structured/semantic logging.

New Features:

• Add native semantic logging support with property extraction - Fixes issue #7932. This release adds comprehensive structured logging support to Akka.NET with both positional ({0}) and named ({PropertyName}) message template parsing, enabling seamless integration with modern logging frameworks like Serilog, NLog, and Microsoft.Extensions.Logging. Key capabilities include:
  • New LogMessage.PropertyNames and GetProperties() APIs for property extraction
  • SemanticLogMessageFormatter as the new default formatter
  • Performance optimized with 75% allocation reduction compared to the previous implementation
  • Zero new dependencies and fully backward compatible
  • EventFilter support for semantic templates in unit tests

1 contributor since release 1.5.56

To see the full set of changes in Akka.NET v1.5.57-beta1, click here

1.5.56 November 25th, 2025

Akka.NET v1.5.56 is a patch release containing important bug fixes for Akka.Remote and Akka.Streams.

Bug Fixes:

• Fix: Akka.Remote should not shutdown on invalid TLS traffic - Fixes issue #7938 where invalid traffic (like HTTP requests) hitting a TLS-enabled Akka.Remote port would cause the entire ActorSystem to shut down. Server now rejects invalid connections gracefully without terminating.

• fix(streams): prevent race condition in ChannelSource on channel completion - Fixes issue #7940 where a NullReferenceException could occur when completing a ChannelWriter while the stream is waiting for data. Added atomic flag to prevent race condition between OnReaderComplete and OnValueRead callbacks.

1 contributor since release 1.5.55

To see the full set of changes in Akka.NET v1.5.56, click here

1.5.55 October 26th, 2025

Akka.NET v1.5.55 is a patch release containing important stability and security improvements for Akka.Remote.

Akka.Remote Stability Improvements:

• Akka.Remote: harden EndpointWriter against serialization failures - Fixes issue #7922 by hardening the EndpointWriter against a broader range of potential serialization failures, improving overall remoting stability.

Akka.Remote Security Improvements:

• Custom certificate validation with single execution path - fixes mTLS asymmetry bug - Fixes issue #7914 by introducing programmatic certificate validation helpers through the new CertificateValidation factory class. This release adds 7 new validation helper methods including ValidateChain(), ValidateHostname(), PinnedCertificate(), ValidateSubject(), ValidateIssuer(), Combine(), and ChainPlusThen(). The update also fixes an mTLS asymmetry bug where server-side hostname validation was not being applied consistently with client-side validation, all while maintaining full backward compatibility with existing HOCON-based validation.

• Fix DotNettySslSetup being ignored when HOCON has valid SSL config - Fixes issue #7917 where programmatic DotNettySslSetup settings were incorrectly being overridden by HOCON configuration. Programmatic configuration now correctly takes precedence over HOCON defaults as intended.

1 contributor since release 1.5.54

To see the full set of changes in Akka.NET v1.5.55, click here

1.5.54 October 17th, 2025

Akka.NET v1.5.54 is a patch release containing important bug fixes for Akka.Streams and Akka.DistributedData.

Bug Fixes:

• Fix SourceRef.Source and SinkRef.Sink non-idempotent property bug - Fixes issue #7895 where ISourceRef<T>.Source and ISinkRef<T>.Sink properties created new stage instances on every access, causing race conditions and intermittent subscription timeouts. These properties are now idempotent using Lazy<T>, preventing failures from accidental property access (debugger inspection, logging, serialization frameworks).

• Fix LWWDictionary.Delta ArgumentNullException when underlying delta is null - Fixes issue #7910 where LWWDictionary.Delta would throw ArgumentNullException when the underlying ORDictionary.Delta was null, which is a legitimate state after initialization or calling ResetDelta().

1 contributor since release 1.5.53

To see the full set of changes in Akka.NET v1.5.54, click here

1.5.53 October 9th, 2025

Akka.NET v1.5.53 is a security patch containing important fixes for TLS/SSL hostname validation and improved error diagnostics for certificate authentication issues.

Security Fixes:

• Fix TLS hostname validation bug and add configurable validation - Fixes a critical bug where TLS clients validated against their own certificate DNS name instead of the remote server address, particularly affecting mutual TLS scenarios. This release also adds a new validate-certificate-hostname configuration option to akka.remote.dot-netty.tcp (defaults to false for backward compatibility) and introduces type-safe validation APIs through the new TlsValidationCallbacks factory class.

Improvements:

• Improve TLS/SSL certificate error messages during handshake failures - Provides human-readable, actionable error messages for TLS/SSL certificate validation failures with detailed troubleshooting guidance, significantly improving the developer experience when configuring certificate-based authentication.

1 contributor since release 1.5.52

To see the full set of changes in Akka.NET v1.5.53, click here

1.5.52 October 6th, 2025

SECURITY PATCH

Akka.NET v1.5.52 is a security patch containing crucial fixes for enforcing certificate-based authentication using mTLS enforcement. Please see https://getakka.net/articles/remoting/security.html for details on how this works.

• Akka.Remote: implement mutual TLS authentication support
• Akka.Remote: validate SSL certificate private key access at server startup

Other fixes:

• Akka.Cluster.Sharding: ShardedDaemonSets: randomize starting worker index

1 contributors since release 1.5.51

To see the full set of changes in Akka.NET v1.5.52, click here

1.5.51 October 1st, 2025

Akka.NET v1.5.51 is a minor patch containing a remoting bug fix and add required codes to support persistence health check.

• Remote: Fix DotNetty TLS handshake error handling
• Persistence: Add health check handling code

2 contributors since release 1.5.50

To see the full set of changes in Akka.NET v1.5.51, click here

1.5.50 September 22nd, 2025

Akka.NET v1.5.50 is a minor patch containing a bug fix.

• Remote: Propagate error from DotNetty TLS Handshake failure to Akka.Remote

1 contributor since release 1.5.49

To see the full set of changes in Akka.NET v1.5.50, click here

1.5.49 September 10th, 2025

Akka.NET v1.5.49 is a minor patch containing several bug fixes.

• Core: Fix IIS/Windows Service console race condition
• DData: Fix Replicator.ReceiveUnsubscribe boolean logic
• Streams: Fix ConcurrentAsyncCallback with ChannelSource throws NRE

3 contributors since release 1.5.48

To see the full set of changes in Akka.NET v1.5.49, click here

1.5.48 August 21st, 2025

Akka.NET v1.5.48 is a minor patch containing stability improvement to Akka.TestKit.

• TestKit: Fix deadlock during parallel test execution

2 contributors since release 1.5.47

To see the full set of changes in Akka.NET v1.5.48, click here

• Core: Add ILoggingAdapter context enrichment, explicit scopes, and bracketed context output in StandardOutLogger and Xunit logger

1.5.47 August 12th, 2025

Akka.NET v1.5.47 is a minor patch containing several stability improvements to Akka.TestKit.

• TestKit: Replace Thread.Sleep with SpinWait
• TestKit: Fix excessive AggregateException nesting when cancelling ExpectMessageAsync
• TestKit: Add async overload to multi-node TestConductor API
• Core: Move ByteBuffer alias to global using

4 contributors since release 1.5.46

To see the full set of changes in Akka.NET v1.5.47, click here

1.5.46 July 17th, 2025

Akka.NET v1.5.46 is a minor patch containing a fix for the Akka.IO.Dns extension.

• Core: Resolve ManagerClass type from IDnsProvider

3 contributors since release 1.5.45

To see the full set of changes in Akka.NET v1.5.46, click here

1.5.45 July 7th, 2025

Akka.NET v1.5.45 is a minor patch containing bug fixes for Core Akka and Akka.Cluster.Sharding plugin.

• Core: Code modernization, use deconstructor for variable swapping
• Sharding: Fix unclean ShardingConsumerControllerImpl shutdown
• Core: Convert Failure to Exception for Ask<object>
• Core: Fix Settings.InjectTopLevelFallback race condition
• Sharding: Make remembered entities honor supervision strategy decisions

Supervision Strategy For Sharding Remembered Entities

• We've added a SupervisorStrategy property to ClusterShardingSettings. You can use any type of SupervisionStrategy, but it is recommended that you inherit ShardSupervisionStrategy if you're making your own custom supervision strategy.
• Remembered shard entities will now honor SupervisionStrategy decisions and stops remembered entities if the SupervisionStrategy.Decider returned a Directive.Stop or if there is a maximum restart retry limitation.

4 contributors since release 1.5.44

To see the full set of changes in Akka.NET v1.5.45, click here

1.5.44 June 19th, 2025

Akka.NET v1.5.44 is a minor patch that contains a bug fix to the Akka.Persistence plugin.

• Persistence: Make sure that EventSourced timer is canceled when persistent actor is stopped

3 contributors since release 1.5.43

To see the full set of changes in Akka.NET v1.5.44, click here.

1.5.43 June 10th, 2025

Akka.NET v1.5.43 contains several bug fixes and also adds new quality of life features.

• Cluster.Tools: Fix PublishWithAck response message type
• Sharding: Allows sharding delivery consumer to passivate self
• TestKit: Fix CallingThreadDispatcher async context switching
• Persistence.Query: Add non-generic ReadJournalFor API method
• Core: Simplify null checks
• Core: Propagate CoordinatedShutdown reason to application exit code
• Core: Bump AkkaAnalyzerVersion to 0.3.3
• Core: Improve IScheduledTellMsg DeadLetter log message

New Akka.Analyzer Rules

We've added three new Akka.Analyzer rules, AK2003, AK2004, and AK2005. All of them addresses the same Akka anti-pattern where a void async delegate is being passed into the ReceiveActor.Receive<T>() (AK2003), IDslActor.Receive<T>() (AK2004), and ReceivePersistentActor.Command<T>() (AK2005) message handlers.

Here are the documentation for each new rules:

• AK2003 documentation
• AK2004 documentation
• AK2005 documentation

4 contributors since release 1.5.42

To see the full set of changes in Akka.NET v1.5.43, click here.

Changes:

• 8223e14 Update RELEASE_NOTES.md for 1.5.62 release (#8074)
• 958ae1b Update RELEASE_NOTES.md for 1.5.62 release (#8074)
• 79b8c0d fix: catch FormatException in log message formatters to prevent third-party logger crashes (#8070) (#8073)

This list of changes was auto generated.