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

Changes:

• 2492bdb Prepare v1.5.55 release (#7926)
• 2dc1c57 Akka.Remote: harden EndpointWriter against serialization failures (#7923) (#7925) [ #7922 ]
• 98c25d1 feat(remote): custom certificate validation with single execution path - fixes mTLS asymmetry bug (#7915) (#7921) [ #7914 ]
• 1e8d606 Fix DotNettySslSetup being ignored when HOCON has valid SSL config (#7918) (#7919) [ #7917 ]
• 77ba03c Prepare v1.5.54 release (#7913)

This list of changes was auto generated.

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

Changes:

• e7bf0c7 Prepare v1.5.54 release
• eb020d0 Fix LWWDictionary.Delta ArgumentNullException when underlying delta is null (#7910) (#7911) (#7912)
• 53e1b3d [v1.5] Fix SourceRef.Source and SinkRef.Sink non-idempotent property bug (#7907) [ #7895 ]
• e1c4b4f Prepare v1.5.53 release (#7900)

This list of changes was auto generated.

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

Changes:

• dfee7bb Prepare v1.5.53 release
• 4eaf307 Fix TLS hostname validation bug and add configurable validation (#7897) [ #7893 ]
• 8644c59 Improve TLS/SSL certificate error messages during handshake failures (#7891) [ #7890 ]

This list of changes was auto generated.

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

Changes:

• b4fbd5f added v1.5.52 release notes (#7883)
• 5f8e39d ShardedDaemonSets: randomize starting worker index (#7857) (#7874)
• 1a5a82b feat(remote): implement mutual TLS authentication support (#7851) (#7855) [ #538 ]
• 5994efc Fix: Validate SSL certificate private key access at server startup (#7847) (#7848) [ #538 ]

This list of changes was auto generated.

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

Changes:

• 68dbe75 Update RELEASE_NOTES.md for 1.5.51 release (#7844)
• ba5e5f8 Akka.Persistence HealthChecks (#7842)
• 1ec6f9e Fix TLS handshake error handling (#7839)

This list of changes was auto generated.

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

Changes:

• 94124ba Update RELEASE_NOTES.md for 1.5.50 release (#7837)
• f595a84 Propagate error from DotNetty TLS handshake failure to Akka.Remote (#7824)

This list of changes was auto generated.

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

Changes:

• 2f19644 Update RELEASE_NOTES.md for 1.5.49 release (#7818)
• 4168945 GraphStageLogic.ConcurrentAsyncCallback throws NRE when used with ChannelSource (#7808)
• 9863fdf fix Replicator.ReceiveUnsubscribe boolean logic (#7806) (#7809) [ #7804 ]
• dceca50 Fix IIS/Windows Service console race condition (#7691) (#7793)
• f2c311f Parameterize Incrementalist base branch for Azure DevOps pipelines (#7791)

This list of changes was auto generated.

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

Changes:

• 1f4c6d2 Update RELEASE_NOTES.md for 1.5.48 release (#7788)
• 0bfe2fc Port #7772 - TestKit: synchronous TestActor start (#7787) [ #7770 ]
• 1f14b74 Convert Akka.Cluster.Sharding.Tests.MultiNode to async (#7758)
• 31adf92 Convert Akka.Cluster.Tests.MultiNode specs to async (#7755)
• 89e6405 Convert Akka.Cluster.Tools multi-node tests to async (#7757)
• f422b79 Update RELEASE_NOTES.md for 1.5.48 nightly (#7760)
• 43f3e52 Convert Akka.Remote.Tests.MultiNode specs to async (#7756)

This list of changes was auto generated.

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

Changes:

• 83e4bcc Update RELEASE_NOTES.md for 1.5.47 release (#7759)
• eef6fe5 Convert SBR multi-node tests to async (#7754)
• 599e13b Convert ClusterRoundRobinSpec to async (#7752)
• 79ec342 move ByteBuffer alias to a global using (#7681)
• f1962c6 Add async overloads to multi-node TestConductor APIs (#7750) [ #4146 ]
• 673f56f Fix excessive exception nesting when cancelling ExpectMsgAsync (#7747) [ #7743 ]
• 28a80b5 Bump actions/checkout from 4 to 5 (#7751)
• f9a1835 Update RELEASE_NOTES.md for 1.5.47 nightly build (#7749)
• a7955cb Fix race condition in AllEventsSpec by using async/await (#7748) [ #7711 ]
• 1c44ee3 add worktrees to .gitignore (#7746)

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

Changes:

• dbca4de Update RELEASE_NOTES.md for 1.5.46 release (#7733)
• 000d75b DnsExt: Resolve ManagerClass Type from IDnsProvider (#7727)
• c10cfc1 docs: added Akka.Cluster SBR video to docs (#7725)
• 3994208 Exclude Akka.Cluster.Cpu.Benchmark from nuget pack (#7724)

This list of changes was auto generated.