<a id="dotnet-changelog"></a>

# Kafka .NET Client Changelog

## 2.13.2

### Enhancements

* Preserve inner exceptions in RestService.

### Fixes

* Support multi-certificate PEM bundles in Schema Registry SslCaLocation.

## 2.13.1

### Enhancements

* Unify build configurations and remove redundant properties.
* JSONSchema Validation Errors: Include paths to nested properties.
* Add Confluent-Client-Version header to requests to SR, .NET Client.

### Fixes

* Fix DeriveKey in Hkdf implementation.
* Ensure single use of HttpRequestMessage for token fetch.
* Fix race conditions when retrieving KEK/DEK.
* Ensure JSON schema access is thread-safe.
* Use lock on root schema when protecting access to sub-schemas.
* Processing arrays and maps sequentially to avoid race conditions.

## 2.13.0

### Enhancements

* References librdkafka.redist 2.13.0. Refer to the [librdkafka v2.13.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.13.0) for more information.
* Support Avro schema references for .NET Client.
* Add Accept-Version header.
* Handle evolution during field transformation.
* Re-enable deserialization optimization by removing unnecessary array conversions.

### Fixes

* Ensure schemaId initialization is thread-safe.
* Ensure all deps are strongly named.

## 2.12.0

### KIP-848 – General Availability

Starting with Confluent.Kafka 2.12.0, the next generation consumer group rebalance protocol defined in KIP-848 is production-ready. Please refer to the following [migration guide](doc/kip-848-migration-guide.md) for moving from `Classic` to `Consumer` protocol.

#### NOTE
The new consumer group protocol defined in [KIP-848](https://cwiki.apache.org/confluence/display/KAFKA/KIP-848%3A+The+Next+Generation+of+the+Consumer+Rebalance+Protocol) is not enabled by default. There are few contract change associated with the new protocol and might cause breaking changes. `GroupProtocol` configuration property dictates whether to use the new `Consumer` protocol or older `Classic` protocol. It defaults to `Classic` if not provided.

### Enhancements

* References librdkafka.redist 2.12.0. Refer to the [librdkafka v2.12.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.12.0) for more information.
* OAuth OIDC method example for Kafka metadata based authentication with an Azure IMDS endpoint using an attached managed identity as principal.

## 2.11.1

### Enhancements

* References librdkafka.redist 2.11.1. Refer to the [librdkafka v2.11.1 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.11.1) for more information.

## 2.11.0

### Enhancements

* References librdkafka.redist 2.11.0. Refer to the [librdkafka v2.11.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.11.0) for more information.

## 2.10.1

### Enhancements

* References librdkafka.redist 2.10.1. Refer to the [librdkafka v2.10.1 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.10.1) for more information.
* Refactor serializer implementations to remove unnecessary ContinueWith calls.
* Remove shared mutex from CachedSchemaRegistryClient.
* Protobuf serialization perf improvements.
* Refactor AuthenticationHeaderValueProvider construction.
* Remove redundant ConfigureAwait.
* Support for schema id in header.
* Use vectorized null-terminated C-string parsing in PtrToStringUTF8 for .NET 6+.
* Rework SchemaId encoding in headers to minimize heap allocations.
* Raise an error if Protobuf deprecated format is specified.
* Avoid array copy on Avro deserialization.

### Fixes

* Fix JSON Schema validation to use latest schema if needed.
* Minor check for null client.
* Fix possible NPE in CSFLE executor.
* Add missing ConfigureAwait calls.
* Fix rule transformation of list properties.

## 2.10.0

### Enhancements

* References librdkafka.redist 2.10.0. Refer to the [librdkafka v2.10.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.10.0) for more information.
* [KIP-848] Group Config is now supported in AlterConfigs, IncrementalAlterConfigs and DescribeConfigs.

## 2.9.0

### Enhancements

* Add utilities to convert decimals to or from Protobuf.
* Add client credentials OAuth support.
* Add support for passing schema ID during serialization.
* Optimize schema registry client by caching results of LookupSchemaAsync.
* Use ConcurrentDictionary as default cache for Schema Registry client.

### Fixes

* Fix JSON Schema validation to use latest schema if needed.
* Support Protobuf oneof fields in Data Contract rules.

## 2.8.0

### Enhancements

* References librdkafka.redist 2.8.0. Refer to the [librdkafka v2.8.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.8.0) for more information.
* Add retry logic to RestService for Schema Registry.
* Add config for validating payloads against JSON Schema.
* Add ability to override disable flag and actions on a rule.
* Add AWS AssumeRole support to AWS KMS.

### Fixes

* Retrieve version for writer schema when getting migrations.
* Add missing JSON Schema validate check.
* Ensure different key ids use different client instances.
* DGS-19409 Ensure Avro serde caches per subject.
* Update hash code for schema references so they can be retrieved correctly.

## 2.6.1

### Enhancements

* References librdkafka.redist 2.6.1. Refer to the [librdkafka v2.6.1 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.6.1) for more information.

### Fixes

* Fix to continue supporting .NET Framework 4.6.2+ in core client library.
* Fix JSON Schema handling to not require use of `$id`.
* Update Caching.Memory to 8.0.1 to address CVE.
* Added Qualified and Custom reference name strategy approaches for Protobuf references.
* Fix validate of SSL CA certs in Schema Registry client.
* Skip SSL certs validation when configured in Schema Registry client.
* Allow proxy to be specified in Schema Registry client.

## 2.6.0

### Enhancements

* References librdkafka.redist 2.6.0. Refer to the [librdkafka v2.6.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.6.0) for more information.
* [KIP-848 EA](https://cwiki.apache.org/confluence/display/KAFKA/KIP-848%3A+The+Next+Generation+of+the+Consumer+Rebalance+Protocol): Admin API for listing consumer groups now has an optional filter to return only groups of given types.
* [KIP-460](https://cwiki.apache.org/confluence/display/KAFKA/KIP-460%3A+Admin+Leader+Election+RPC) Admin Leader Election RPC.
* .NET 8 support with NJsonSchema 11.

## 2.5.3

### Enhancements

* References librdkafka.redist 2.5.3. Refer to the [librdkafka v2.5.3 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.5.3) for more information.

### Fixes

* Properly handle messages with well-known types in Protobuf serializer.
* Use AES128_GCM in the Local KMS client, for consistency with Java and Go.
* Include deleted schemas when getting schemas by subject and version.
* Handle signed integers when transforming Protobuf payloads.
* Allow null SchemaRegistryClient in AsyncSerde constructor.

## 2.5.2

#### WARNING
Versions 2.5.0, 2.5.1 and 2.5.2 have a regression in which an assert is triggered during PushTelemetry call. This happens when no metric is matched on the client side among those requested by broker subscription.

You won’t face any problem if:

* Broker doesn’t support [KIP-714](https://cwiki.apache.org/confluence/display/KAFKA/KIP-714%3A+Client+metrics+and+observability).
* [KIP-714](https://cwiki.apache.org/confluence/display/KAFKA/KIP-714%3A+Client+metrics+and+observability) feature is disabled on the broker side.
* [KIP-714](https://cwiki.apache.org/confluence/display/KAFKA/KIP-714%3A+Client+metrics+and+observability) feature is disabled on the client side. This is enabled by default. Set configuration `enable.metrics.push` to `false`.
* If [KIP-714](https://cwiki.apache.org/confluence/display/KAFKA/KIP-714%3A+Client+metrics+and+observability) is enabled on the broker side and there is no subscription configured there.
* If [KIP-714](https://cwiki.apache.org/confluence/display/KAFKA/KIP-714%3A+Client+metrics+and+observability) is enabled on the broker side with subscriptions that match the [KIP-714](https://cwiki.apache.org/confluence/display/KAFKA/KIP-714%3A+Client+metrics+and+observability) metrics defined on the client.

You should use `v2.5.3` and above to avoid this regression.

### Fixes

* Fix client-side field-level encryption (CSFLE) to use the Google Tink format for DEKs for interoperability with clients in other languages (Java, Go, etc.).
* Improve error when specifying an invalid KMS type for CSFLE.
* Enhance CSFLE examples with KMS configuration settings.

## 2.5.1

### Fixes

* Fix client-side field-level encryption (CSFLE) when using Azure Key Vault by specifying RsaOaep256 (instead of RsaOaep) for interoperability with clients in other languages (Java, Go, etc.).
* Fix AvroSerializer configuration to allow using schema normalization.
* Upgrade Azure Identity library to 1.11.4 to address a vulnerability in previous versions.

## 2.5.0

### Enhancements

* References librdkafka.redist 2.5.0. Refer to the [librdkafka v2.5.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.5.0) for more information.
* Add support for metadata and ruleSet in the schema registry client, which together support data contracts.
* Add support for client-side field-level encryption (CSFLE) for AWS, Azure, Google Cloud, and HashiCorp Vault.  See the encryption examples in the examples directory.
* Add support for CEL, CEL_FIELD, and JSONata rules.

### Fixes

* Switch license expression and other repo information.

## 2.4.0

### Enhancements

* References librdkafka.redist 2.4.0. Refer to the [librdkafka v2.4.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.4.0) for more information.
* [KIP-848 EA](https://cwiki.apache.org/confluence/display/KAFKA/KIP-848%3A+The+Next+Generation+of+the+Consumer+Rebalance+Protocol): Added KIP-848 based new consumer group rebalance protocol. Integration tests running with the new consumer group protocol. This feature is in early access and is not suitable for production environments. Please refer [detailed doc](https://github.com/confluentinc/librdkafka/blob/master/INTRODUCTION.md#next-generation-of-the-consumer-group-protocol-kip-848) for more information.

## 2.3.0

### Enhancements

* References librdkafka.redist 2.3.0. Refer to the [librdkafka v2.3.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.3.0) for more information.
* [KIP-430](https://cwiki.apache.org/confluence/display/KAFKA/KIP-430+-+Return+Authorized+Operations+in+Describe+Responses): Return authorized operations in describe responses.
* [KIP-396](https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=97551484): Added support for ListOffsets Admin API.
* Add `Rack` to the `Node` type, so AdminAPI calls can expose racks for brokers (currently, all Describe Responses).
* Added support for external JSON schemas in `JsonSerializer` and `JsonDeserializer`.
* Added compatibility methods to CachedSchemaRegistryClient.
* Add support for AdminAPI `DescribeCluster()` and `DescribeTopics()`.

## 2.2.0

### Enhancements

* References librdkafka.redist 2.2.0. Refer to the [librdkafka v2.2.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.2.0) for more information.
* [KIP-339](https://cwiki.apache.org/confluence/display/KAFKA/KIP-339%3A+Create+a+new+IncrementalAlterConfigs+API) IncrementalAlterConfigs API.
* [KIP-554](https://cwiki.apache.org/confluence/display/KAFKA/KIP-554%3A+Add+Broker-side+SCRAM+Config+API): User SASL/SCRAM credentials alteration and description.

### Fixes

* Fix backwards compatibility of TopicPartitionOffset constructor.
* Fix IConsumer breaking change.

## 2.1.1

### Enhancements

* References librdkafka.redist 2.1.1. Refer to the [librdkafka v2.1.1 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.1.1) for more information.
* Less heap allocations when calling Produce.

## 2.1.0

### Enhancements

* References librdkafka.redist 2.1.0. Refer to the [librdkafka v2.1.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.1.0) for more information.
* Added SetSaslCredentials. This new method on the Producer, Consumer, and AdminClient allows modifying the stored SASL PLAIN/SCRAM credentials that will be used for subsequent new connections to a broker.
* Changed the way the `_SCHEMA` filed is accessed internally from reflecting the static field to accessing it from the instance.
* [KIP-320](https://cwiki.apache.org/confluence/display/KAFKA/KIP-320%3A+Allow+fetchers+to+detect+and+handle+log+truncation): add offset leader epoch fields to the TopicPartitionOffset, TopicPartitionOffsetError and ConsumeResult classes.

### Fixes

* Fixed `OverflowException` thrown intermittently when using the `ListGroup` method.

## 2.0.2

### Upgrade considerations

OpenSSL 3.0.x upgrade in librdkafka requires a major version bump, as some legacy ciphers need to be explicitly configured to continue working, but it is highly recommended not to use them. The rest of the API remains backward compatible.

### Enhancements

* References librdkafka.redist 2.0.2. Refer to the [librdkafka v2.0.0 release notes](https://github.com/edenhill/librdkafka/releases/tag/v2.0.0) and later ones for more information.
* Upgraded `NJsonSchema` to v10.6.3.
* Added `LatestCompatibilityStrict` configuration property to JsonSerializerConfig to check the compatibility with latest schema when `UseLatestVersion` is set to true.
* Added DeleteConsumerGroupOffset to AdminClient.
* [KIP-222](https://cwiki.apache.org/confluence/display/KAFKA/KIP-222+-+Add+Consumer+Group+operations+to+Admin+API) Finish remaining implementation: Add Consumer Group operations to Admin API. `DeleteGroups` is already present.
* [KIP-518](https://cwiki.apache.org/confluence/display/KAFKA/KIP-518%3A+Allow+listing+consumer+groups+per+state) Allow listing consumer groups per state.
* [KIP-396](https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=97551484) Partially implemented: support for AlterConsumerGroupOffsets.
* As result of the above KIPs, added.
  * `ListConsumerGroups` Admin operation. Supports listing by state.
  * `DescribeConsumerGroups` Admin operation. Supports multiple groups.
  * `ListConsumerGroupOffsets` Admin operation. Currently, only supports one group with multiple partitions. Supports the `requireStable` option.
  * `AlterConsumerGroupOffsets` Admin operation. Currently, only supports one group with multiple offsets.

### Fixes

* During a group rebalance, partitions are now always revoked as a side effect of a call to Consume, whether or not a partitions revoked handler has been specified. Previously, if no handler was specified, the timing of when the consumer lost ownership of partitions during a rebalance was arbitrary, frequently resulting in an erroneous state exception when committing or storing offsets.
* Fixed 100% CPU usage with `DependentAdminClientBuilder`.

#### NOTE
There were no 2.0.0 and 2.0.1 releases.

## 1.9.3

### Enhancements

* Added `NormalizeSchemas` configuration property to the Avro, Json and Protobuf serdes.

### Fixes

* Schema Registry authentication now works with passwords that contain the ‘:’ character.
* Added missing librdkafka internal and broker error codes to the `ErrorCode` enum.

## 1.9.2

### Enhancements

* References librdkafka.redist 1.9.2 which includes an Apple M1 librdkafka build.
* Added ACL AdminClient operations for CreateAcls, DescribeAcls, DeleteAcls.
* Added DeleteGroups to AdminClient.
* Enhanced the Avro Specific Deserializer to ignore the type namespace.
* Improved efficiency of the statistics handler.

### Fixes

* The AdminClient poll loop no longer terminates when a request results in an error.
* Upgraded Newtonsoft.Json to 13.0.1 to address a security vulnerability in 9.0.1.

## 1.9.1

There was no 1.9.1 release of the .NET Client.

## 1.9.0

### Enhancements

* References librdkafka.redist 1.9.0. Refer to the [librdkafka release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.9.0) for a complete list of changes, enhancements, fixes and upgrade considerations.
* References Apache.Avro 1.11.0. Refer to the [release notes](https://github.com/apache/avro/releases/tag/release-1.11.0) for further information.
* Added support for serializing and deserializing null in Avro serdes.
* Enhanced CachedSchemaRegistryClient to allow for user-implemented authentication schemes.
* Reduced memory use when producing with delivery reports disabled.

### Fixes

* Resolved incompatibility with Apple M1 processors.
* No longer crashes on Alpine Linux when MUSL is installed.
* JSON validation exception messages now properly include failing paths.
* Upgraded Google.Protobuf dependency to 3.15.0 for CVE-2021-22570.
* Resolved memory leak in AdminClient response handler.
* Resolved memory leak in Producer.SendOffsetsToTransaction.

### Upgrade Considerations

* The earliest supported .NET Framework version is now 4.6.2, previously this was 4.5.

## 1.8.2

### Enhancements and Fixes

* References librdkafka.redist 1.8.2. Refer to the [librdkafka release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.8.2) for a complete list of changes, enhancements, fixes and upgrade considerations.
* Added the SslCaPem configuration property to specify a CA certificate using a PEM string.

## 1.8.1

### Enhancements

* Updated `NJsonSchema` to v10.5.2.

## 1.8.0

### Enhancements

* References librdkafka.redist 1.8.0. Refer to the [librdkafka release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.8.0) for a complete list of changes, enhancements, fixes and upgrade considerations.
* Added the `UseLatestVersion` configuration property to the Protobuf, JSON Schema and Avro serdes.

### Fixes

* Breaking Change: Updated the message framing format used by the Protobuf SerDes in `ProtobufSerializer` and `ProtobufDeserializer` to be compatible with the Java Protobuf SerDes. Message indices now use zigzag encoding.

  #### NOTE
  This framing encodes schema metadata, enabling integration with Confluent Schema Registry. To disable, set the `UseDeprecatedFormat` configuration property to `true`.

### Security

* Upgraded the bundled zlib version from 1.2.8 to 1.2.11 in the librdkafka.redist NuGet package. The updated zlib version fixes CVEs: CVE-2016-9840, CVE-2016-9841, CVE-2016-9842, CVE-2016-9843.
  See [https://github.com/edenhill/librdkafka/issues/2934](https://github.com/edenhill/librdkafka/issues/2934) for more information.

## 1.7.0

### Enhancements

* References librdkafka.redist 1.7.0. Refer to the [librdkafka release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.7.0) for a complete list of changes, enhancements, fixes and upgrade considerations.
* Added OAuth support to AdminClient

### Fixes

* Resolved a schema caching bug [#1587](https://github.com/confluentinc/confluent-kafka-dotnet/pull/1587) in `CachedSchemaRegistryClient.GetSchemaIdAsync`.
* Fixed a configuration error in the Web example.

### Security

* Updated `System.Net.Http` dependency to v4.3.4 for [CVE-2018-8292](https://github.com/advisories/GHSA-7jgj-8wvc-jh57).

## 1.6.3

### Fixes

* References Apache.Avro v1.10.2, which resolves an issue with large string deserialization [AVRO-3005](https://issues.apache.org/jira/browse/AVRO-3005).

## 1.6.2

### Enhancements

* References librdkafka.redist 1.6.1. Refer to the [1.6.0](https://github.com/edenhill/librdkafka/releases/tag/v1.6.0) and [1.6.1](https://github.com/edenhill/librdkafka/releases/tag/v1.6.1) release notes for more information. Headline features:
  * KIP-429: Incremental rebalancing.
  * KIP-447: Producer scalability for exactly once semantics.
  * KIP-480: Sticky partitioner.
* KIP-22: Support for custom partitioners.
* Confluent.Kafka can now be used with Mono on Linux and MacOS.

  #### NOTE
  Mono is not a supported runtime.
* The debian9-librdkafka.so build of librdkafka has been replaced with a more portable one: centos6-librdkafka.so.

  #### NOTE
  Debian 9 is still supported.
* Exceptions thrown by `Producer.Produce` now include an inner exception with additional context on the error.
* Added `ConfigureAwait(false)` to async methods in the Avro Serdes.
* Added `IsInvalid` property to `Handle` class.

### Fixes

* Fixed race condition in `ProtobufSerializer`.

### 1.6.0, 1.6.1

Version 1.6.0 and 1.6.1 were not released.

## 1.5.3

### Enhancements

* References librdkafka 1.5.3. Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.5.3) for more information.
* References Apache.Avro v1.10.1, which adds support for enum defaults [AVRO-2750](https://issues.apache.org/jira/browse/AVRO-2750).

## 1.5.2

### Enhancements

* References librdkafka 1.5.2. Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.5.2) for more information.
* Avro serializer now supports generic parameter `ISpecificRecord`. In this case, data is serialized according to the per-message concrete type.

## 1.5.1

### Enhancements

* Added support for OAuth Authentication via SASL/OAUTHBEARER for KIP-255.

## 1.5.0

### Enhancements

* References librdkafka 1.5.0 which brings many small improvements and bug fixes.
  Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.5.0) for more information.
* Added support for Schema Registry SSL Authentication.

## 1.4.4

### Fixes

* Resolved a stack overflow issue in `Error(IntPtr error)` [#1249](https://github.com/confluentinc/confluent-kafka-dotnet/issues/1249)
* References librdkafka 1.4.4. Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.4.4) for more information.

## 1.4.3

### Fixes

* Subject names are now URL encoded when used in Schema Registry URLs.
* Fixed a memory leak that occurred when passing a `CancellationToken` to `Producer.ProduceAsync`.

## 1.4.2

### Fixes

* Maintenance release. Refer to the [librdkafka release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.4.2) for more information.
* Fixed incorrect content-type header in Schema Registry HTTP requests.

## 1.4.0

### Enhancements

* References librdkafka v1.4.0. Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.4.0) for more information. Headline features:
  * KIP-98: Producer support for transactions.
    This is the final improvement required to enable exactly once stream (EOS) processing in .NET.
  * KIP-345: Static consumer group membership.
  * KIP-511: Client name and version are now provided to brokers.
* Added Protobuf and JSON serdes including integration with Schema Registry.
* Switched to the official Apache Avro [nuget package](https://www.nuget.org/packages/Confluent.Apache.Avro/), which includes support for [logical types](https://avro.apache.org/docs/current/spec.html#Logical+Types), and all fixes from the [Confluent fork](https://github.com/confluentinc/avro/tree/confluent-fork), which has now been discontinued.
* Message headers are now exposed to serdes via `SerializationContext`.
* Added a `CancellationToken` parameter to the `ProduceAsync` methods.
* Uncaught exceptions thrown in handler methods are now propagated to the initiating function, or in the case of error or log events, ignored. Previously, they would cause the application to terminate.
* Added a [WordCount](https://github.com/confluentinc/confluent-kafka-dotnet/tree/master/examples/Transactions) example demonstrating a streaming map-reduce application with exactly-once processing.

### Changes

* Some internal improvements to the `Consumer`.
* Breaking change: `net452` is no longer a target framework of `Confluent.SchemaRegistry` or `Confluent.SchemaRegistry.Serdes` due to the switch to the official Apache Avro package which only targets `netstandard2.0`.
* Marked properties on `ConsumeResult` that simply delegate to the corresponding properties on `ConsumeResult.Message` as obsolete.

### Fixes

* Fixed an `ArgumentNullException` regression in `ListGroups`.

## 1.3.0

### Enhancements

* Added support for [Subject Name Strategies](https://www.confluent.io/blog/put-several-event-types-kafka-topic/) to `Confluent.SchemaRegistry`.
* `ConsumeResult` now throws `MessageNullException`, not `NullReferenceException` when a message property is accessed but no message exists.
* References librdkafka v1.3.0. Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.3.0) for more information. Headline feature is support for fetch from follower for KIP-392.

### Changes

* Deprecated properties of `SchemaRegistryConfig` with the unnecessary prefix `SchemaRegistry`.
  Added corresponding properties without this prefix.

### Fixes

* Resolved issue [993](https://github.com/confluentinc/confluent-kafka-dotnet/issues/993) whereby `RestService` was unable to communicate with Schema Registry hosted on a non-root path.

## 1.2.2

* References librdkafka v1.2.2 which upgrades the lz4 dependency to v1.9.2.

## 1.2.1

### Fixes

* References librdkafka v1.2.1 which resolves an issue that broke GSSAPI authentication on Windows.

## 1.2.0

### Bugs

#### WARNING
There is an issue with SASL GSSAPI authentication on Windows with this release. This is resolved in v1.2.1.

### Enhancements

* References librdkafka v1.2.0. Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.2.0) for more information. Headline feature is consumer side support for transactions.
* Added `IDictionary` overload to `Config` constructors.
* `Confluent.Kafka`, `Confluent.SchemaRegistry` and `Confluent.SchemaRegistry.Serdes` are now all signed, and `Confluent.Kafka.StrongName` deprecated.

### Fixes

* Updated the librdkafka build load order so that the version with the most features is used on any given platform.

## 1.1.0

### Enhancements

* References librdkafka v1.1.0. Refer to the [release notes](https://github.com/edenhill/librdkafka/releases/tag/v1.1.0) for more information. Notable improvement for Windows SSL users: You no longer need to specify a CA certificate file/directory (`SslCaLocation`). Librdkafka will load the CA certs by default from the Windows Root Certificate Store.

### 1.0.1.1

### Changes

* Applied `ConfigureAwait(false)` to all internal `await` calls, which resolves deadlock issues in synchronization contexts with limited numbers of threads [#967](https://github.com/confluentinc/confluent-kafka-dotnet/pull/967).

## 1.0.1

### Enhancements

* Support for Alpine Linux.
* New LogLevelType enum and functions to convert between different log level type levels.
* Added netstandard20 as a target.
* References librdkafka [1.0.1](https://github.com/edenhill/librdkafka/releases/tag/v1.0.1).

## 1.0.0

### Summary

1.0.0 is a major update of the API, introducing many new features and enhancements.

> #### NOTE
> The 1.0 API is not compatible with earlier versions of the library.

Feature highlights:

* Inherits all of the new features in librdkafka [v1.0.0](https://github.com/edenhill/librdkafka/releases/tag/v1.0.0)
* General improvements to client classes:
  * Strongly typed configuration.
  * Construction is by builder classes:
    * Allows or enforces that event handlers are specified at construction time.
    * More extensible.
  * Header support.
  * New Message class abstraction and related changes.
  * Consistency in error reporting across library by exceptions.
  * Support for fatal errors.
* Added AdminClient:
  * CreateTopics, DeleteTopics, CreatePartitions, AlterConfigs, and DescribeConfigs methods.
  * Moved ListGroups and GetMetadata methods from the Producer and Consumer classes to AdminClient.
* Producer specific improvements:
  * New serialization interface:
    * Non-blocking support for async serializers.
    * Very flexible. For example, can be easily extended to support header serialization.
  * Capability to specify custom timestamps when producing messages.
  * Message persistence status support.
  * Renamed ProduceAsync variants with a callback to Produce.
* Consumer improvements:
  * A new rebalance API.
  * New deserialization API analogous to the new serialization API.
  * PartitionEOF notification is via ConsumeResult, not events.
    * EOF notification is now disabled by default. To enable, set the EnablePartitionEof config property to true.
* Confluent Schema Registry integration.
  * Added support for basic authentication.
  * Added GET subject versions to the cached schema registry client.
  * Renamed Confluent.Kafka.Avro to Confluent.SchemaRegistry.Serdes in preparation for support for additional serialization formats.

## 1.0.0-RC7

### Changes

* Moved SyncOverAsync functionality to the Confluent.Kafka.SyncOverAsync namespace.
* Marked DependentProducerBuilder as API-SUBJECT-TO-CHANGE.
* No-op handlers are no longer registered with librdkafka if corresponding handlers are not specified in client builder classes.
* Renamed AsyncAvroSerializer to AvroSerializer and AsyncAvroDeserializer to AvroDeserializer.

## 1.0.0-RC6

### New Features

* Added DependentAdminClientBuilder class.

### Changes

* Reverted RC4 changes.
* Renamed AvroSerializer to AsyncAvroSerializer and AvroDeserializer to AsyncAvroDeserializer.
* Added SyncOverAsyncSerializer and SyncOverAsyncDeserializer adapter classes.
* Added AsSyncOverAsync factory method to AsyncAvroSerializer and AsyncAvroDeserializer.
* Removed IAsyncDeserializer setter overloads from the ConsumerBuilder class.
* Renamed Producer.BeginProduce to Producer.Produce.
* Produce throws an exception if used when async serializers are configured.
* Made AdminClient, Producer, and Consumer classes internal.

## 1.0.0-RC4

### Changes

* Removed `SerializationContext` from non-async serde interfaces.
* Replaced `ISerializer` interface with `Serializer` delegate.
* Replaced `IDeserializer` interface with `Deserializer` delegate.

## 1.0.0-RC3

### New Features

* `Producer.Poll` can now be used with producer instances that are in background polling mode.
  * Typically use: Block for a minimal period of time following a `ErrorCode.Local_QueueFull` error.

### Changes

* Removed the `Confluent.Kafka.Serdes` namespace.

### Fixes

* Added `CompressionType` property to `ProducerConfig` class.

## 1.0.0-RC2

### New Features

* References librdkafka.redist [v1.0.0](https://github.com/edenhill/librdkafka/releases/tag/v1.0.0)

### Changes

* Moved API docs from the client classes to their respective interfaces.
* Update formatting of client API docs so they display well in Visual Studio Code intellisense.

## 1.0.0-RC1

### New Features

* Added GET subject versions to the cached schema registry client.
* References librdkafka.redist [1.0.0-RC9](https://github.com/edenhill/librdkafka/releases/tag/v1.0.0-RC9)
  * Supports Alpine Linux out-of-the-box.
  * Fallback support that excludes security features for most Linux distributions previously unsupported out-of-the-box.
  * Fixed a dependency issue on MacOS.

### Changes

* A new rebalance API. `ISerializer<T>`, `IAsyncSerializer<T>`, `IDeserializer<T>`, and `IAsyncDeserializer<T>`
  * `SetRebalanceHandler` has been split into `SetPartitionsAssignedHandler` and `SetPartitionsRevokedHandler`.
  * Calling of `Assign` or `Unassign` in these handlers is prohibited.
  * Partitions to read from or start offsets can be optionally specified manually via the return value from these handlers.
* The `Message.PersistenceStatus` property name has changed to `Message.Status`.
* Moved the `GetWatermarkOffsets` and `QueryWatermarkOffsets` methods from admin client to consumer.
* Context is now provided to serdes via a `SerializationContext` class instance.

### Fixes

* Corrected an error in the `rd_kafka_event_type` method signature which was causing incompatibility with mono.
* Audited exception use across the library and made changes in various places where appropriate.
* Removed unused `CancellationToken` parameters.
* Builder classes now return interfaces, not concrete classes.
* Removed the dependency on `CompilerServices.Unsafe` which was causing `ProduceAsync` to hang in some scenarios.
* Fixed a deadlock-on-dispose issue in `AdminClient`.
* Made `Producer.ProduceAsync` async.

## 1.0.0-beta3

### New Features

* Revamped producer and consumer serialization functionality.
  * There are now two types of serializer and deserializer: `ISerializer<T>`, `IAsyncSerializer<T>`, `IDeserializer<T>`, and `IAsyncDeserializer<T>`.
    * `ISerializer<T>` and `IDeserializer<T>` are appropriate for most use cases.
    * `IAsyncSerializer<T>` and `IAsyncDeserializer<T>` are async friendly, but less performant, returning `Task`.
  * Changed the name of `Confluent.Kafka.Avro` to `Confluent.SchemaRegistry.Serdes`.
  * Added an example demonstrating working with Protobuf serialized data.
* The `Consumer`, `Producer`, and `AdminClient` classes are now constructed using builder classes.
  * This is more verbose, but provides a sufficiently flexible and future proof API for specifying serdes and other configuration information.
  * All `event` classes on the client classes have been replaced with corresponding `Set...Handler` methods on the builder classes.
    * This allows or enforces handlers are set on librdkafka initialization, which is important for some handlers, particularly the log handler.
    * `event` allows for more than one handler to be set, but this is often not appropriate, such as `OnPartitionsAssigned`, and never necessary. This is no longer possible.
    * `event` is also not async friendly. Handlers can’t return `Task`. The Set…Handler approach can be extend in such a way that it is.
* Avro serdes no longer make blocking calls to `ICachedSchemaRegistryClient`. Everything is `await`.

  #### NOTE
  The `Consumer` implementation still calls async deserializers synchronously because the `Consumer` API is still otherwise fully synchronous.
* Reference librdkafka.redist [1.0.0-RC7](https://github.com/edenhill/librdkafka/releases/tag/v1.0.0-RC7)
  * Notable features include idempotent producer, sparse connections, `max.poll.interval.ms` for KIP-62.

  #### NOTE
  End of partition notification is now disabled by default. Enable it using the `EnablePartitionEof` configuration property.
* Removed the `Consumer.OnPartitionEOF` event in favor notifying of partition eof via `ConsumeResult.IsPartitionEOF`.
* Removed `ErrorEvent` class and added `IsFatal` to `Error` class.
  * The `IsFatal` flag is now set appropriately for all errors. This was previously always set to `false`.
* Added `PersistenceStatus` property to `DeliveryResult`, which provides information on the persistence status of the message.

### Fixes

* Added `Close` method to `IConsumer` interface.
* Changed the name of `ProduceException.DeliveryReport` to `ProduceException.DeliveryResult`.
* Fixed bug where enum config property couldn’t be read after setting it.
* Added `SchemaRegistryBasicAuthCredentialsSource` back into `SchemaRegistryConfig`.
* Fixed Schema Registry client failover connection issue.
* Improvements to librdkafka dependency discovery.

## 1.0.0-beta2

### New Features

* References librdkafka [1.0.0-PRE1](https://github.com/edenhill/librdkafka/tree/v1.0.0-PRE1). Highlights:
  * Idempotent producer.
  * Sparse connections, so broker connections are only held open when in use.

### Enhancements and Fixes

* Fixed a memory leak in `ProduceAsync` [#640](https://github.com/confluentinc/confluent-kafka-dotnet/pull/640), which was a regression from 0.11.x.

## 1.0.0-beta

### New Features

* Added an AdminClient, providing `CreateTopics`, `DeleteTopics`, `CreatePartitions`, `DescribeConfigs` and `AlterConfigs`.
* Can now produce and consume message headers.
* Can now produce user defined timestamps.
* Added `IClient`, `IProducer` and `IConsumer` interfaces, which is useful for dependency injection and mocking when writing tests.
* Added a `Handle` property to all clients classes:
  * Producers can utilize the underlying librdkafka handle from other Producers, which replaces the 0.11.x `GetSerializingProducer` method on the `Producer` class.
  * `AdminClient` can utilize the underlying librdkafka handle from `AdminClient`, `Producer`, or `Consumer`.
* `IDeserializer` now exposes message data via `ReadOnlySpan<byte>`, directly referencing librdkafka allocated memory. This results in a considerable performance increase of up to 2x and reduced memory.
* Most blocking operations now accept a `CancellationToken` parameter.
* .NET Specific configuration parameters are all specified and documented in the `ConfigPropertyNames` class.

### Major Breaking API Changes

* The `Message` class has been re-purposed and now encapsulates specifically the message payload only.
  * `ProduceAsync` and `BeginProduce` now return a `DeliveryReport` object and `Consumer.Consume` returns a `ConsumeResult` object.
* The methods used to produce messages have changed:
  * Methods that accept a callback are now named `BeginProduce` instead of `ProduceAsync`, analogous to similar methods in the standard library.
  * Callbacks are now specified as `Action<DeliveryReportResult<TKey, TValue>>` delegates, not implementations of `IDeliveryHandler`.
  * The `IDeliveryHandler` interface has been deprecated.
  * There are two variants of `ProduceAsync` and `BeginProduce`, the first takes a topic name and a `Message`. The second takes a `TopicPartition` and a message.
    * In other words, when producing, there is now clear separation between what is produced and where it is produced to.
  * The new API is more future proof.
  * `ProduceAsync` now calls `SetException` instead of `SetResult` on the returned `Task`, making error checking more convenient and less prone to developer mistakes.
* The feature to block `ProduceAsync` calls on local queue full has been removed, which results in `Local_QueueFull` error. This should be implemented at the application layer if required.
* The non-serializing `Producer` and non-deserializing `Consumer` types have been removed, which uses generic types with `byte[]` instead, considerably reducing API surface area.
* The `ISerializingProducer` interface has been removed - you can achieve the same functionality by sharing client handles instead.
* The `Consumer.Poll` method and corresponding `OnMessage` event have been removed. You should use `Consumer.Consume` instead.
* The `Consumer.OnConsumeError` has been removed. Consume errors are now exposed via a `ConsumeException`.
* The `Consumer.Consume` method now returns a `ConsumeResult` object rather than a `Message` from an out parameter.
* `CommitAsync` has been removed. Use `Commit` instead.
* `Commit` errors are reported via an exception and method return values have correspondingly changed.
* `ListGroups`, `ListGroup`, `GetWatermarkOffsets`, `QueryWatermarkOffsets`, and `GetMetadata` have been removed from `Producer` and `Consumer` and exposed only from `AdminClient`.
* Added `Consumer.Close`.
* Various methods that formerly returned `TopicPartitionOffsetError` or `TopicPartitionError` now return `TopicPartitionOffset` or `TopicPartition` and throw an exception in case of error with a `Result` property of type `TopicPartitionOffsetError` or `TopicPartitionError`.

### Minor Breaking API Changes

* Removed cast from `Error` to `bool`.
* `Consumer.OffsetsForTimes` if provided an empty collection will return an empty collection, instead of throwing an exception.
* `manualPoll` argument has been removed from the `Producer` constructor and is now a configuration option.
* `enableDeliveryReports` argument has been removed from the `Producer` constructor and is now a configuration option.
* Removed methods with a `millisecondsTimeout` parameter, always preferring a `TimeSpan` parameter.
* Added `Consumer.Consume` variants with a `CancellationToken` parameter.
* Added A `Producer.Flush` method variant without a timeout parameter but with a `CancellationToken` parameter that is observed.
* Added the `SyslogLevel` enumeration, which is used by the log handler delegate.

### Minor Enhancements and Fixes

* When delivery reports are disabled, `ProduceAsync` will return any completed `Task` rather than a `Task` that will never complete.
* Avro serializers and deserializer now handle `null` values.
* Examples upgraded to target 2.1.
* Changed name of `HasError` to `IsError`
* Configuration options have been added to allow fine-grained control over of marshalling of values to and from librdkafka for high performance usage.
  * Headers, message keys and values, timestamps, and the topic name.
* Improved XML API documentation.

## 0.11.5 and previous

Refer to the [release notes](https://github.com/confluentinc/confluent-kafka-dotnet/releases)