Amazon Kinesis Client Library (KCL) 1.x will reach end-of-support on January 30, 2026. Accordingly, these versions will enter maintenance mode on April 17, 2025. During maintenance mode, AWS will provide updates only for critical bug fixes and security issues. Major versions in maintenance mode will not receive updates for new features or feature enhancements. If you’re using KCL 1.x, we recommend migrating to the latest versions. When migrating from KCL 1.x to 3.x, you will need to update interfaces and security credential providers in your application. For details about the end-of-support notice and required actions, see the following links:
* [AWS Blog: Announcing end-of-support for Amazon Kinesis Client Library 1.x and Amazon Kinesis Producer Library 0.x effective January 30, 2026](https://aws.amazon.com/blogs/big-data/announcing-end-of-support-for-amazon-kinesis-client-library-1-x-and-amazon-kinesis-producer-library-0-x-effective-january-30-2026/)
* [Kinesis documentation: KCL version lifecycle policy](https://docs.aws.amazon.com/streams/latest/dev/kcl-version-lifecycle-policy.html)
* [Kinesis documentation: Migrating from KCL 1.x to KCL 3.x](https://docs.aws.amazon.com/streams/latest/dev/kcl-migration-1-3.html)
* [#995](https://github.com/awslabs/amazon-kinesis-client/commit/372f98b21a91487e36612d528c56765a44b0aa86) Every other change for DynamoDBStreamsKinesis Adapter Compatibility
* [#970](https://github.com/awslabs/amazon-kinesis-client/commit/251b331a2e0fd912b50f8b5a12d088bf0b3263b9) PeriodicShardSyncManager Changes Needed for DynamoDBStreamsKinesisAdapter
* [#816](https://github.com/awslabs/amazon-kinesis-client/pull/816) Updated the Worker shutdown logic to make sure that the `LeaseCleanupManager` also terminates all the threads that it has started.
* [#821](https://github.com/awslabs/amazon-kinesis-client/pull/821) Upgrading version of AWS Java SDK to 1.12.3
* [#811](https://github.com/awslabs/amazon-kinesis-client/pull/811) Fixing a bug in `KinesisProxy` that can lead to undetermined behavior during partial failures.
* [#811](https://github.com/awslabs/amazon-kinesis-client/pull/811) Adding guardrails to handle duplicate shards from the service.
* [#790](https://github.com/awslabs/amazon-kinesis-client/pull/790) Fixing a bug that caused paginated `ListShards` calls with the `ShardFilter` parameter to fail when the lease table was being initialized.
* Behavior of shard synchronization is moving from each worker independently learning about all existing shards to workers only discovering the children of shards that each worker owns. This optimizes memory usage, lease table IOPS usage, and number of calls made to kinesis for streams with high shard counts and/or frequent resharding.
* When bootstrapping an empty lease table, KCL utilizes the ListShard API's filtering option (the ShardFilter optional request parameter) to retrieve and create leases only for a snapshot of shards open at the time specified by the ShardFilter parameter. The ShardFilter parameter enables you to filter out the response of the ListShards API, using the Type parameter. KCL uses the Type filter parameter and the following of its valid values to identify and return a snapshot of open shards that might require new leases.
* Currently, the following shard filters are supported:
*`AT_TRIM_HORIZON` - the response includes all the shards that were open at `TRIM_HORIZON`.
*`AT_LATEST` - the response includes only the currently open shards of the data stream.
*`AT_TIMESTAMP` - the response includes all shards whose start timestamp is less than or equal to the given timestamp and end timestamp is greater than or equal to the given timestamp or still open.
*`ShardFilter` is used when creating leases for an empty lease table to initialize leases for a snapshot of shards specified at `KinesisClientLibConfiguration#initialPositionInStreamExtended`.
* For more information about ShardFilter, see the [official AWS documentation on ShardFilter](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_ShardFilter.html).
* Introducing support for the `ChildShards` response of the `GetRecords` API to perform lease/shard synchronization that happens at `SHARD_END` for closed shards, allowing a KCL worker to only create leases for the child shards of the shard it finished processing.
* For KCL 1.x applications, this uses the `ChildShards` response of the `GetRecords` API.
* For more information, see the official AWS Documentation on [GetRecords](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_GetRecords.html) and [ChildShard](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_ChildShard.html).
* KCL now also performs additional periodic shard/lease scans in order to identify any potential holes in the lease table to ensure the complete hash range of the stream is being processed and create leases for them if required. When `KinesisClientLibConfiguration#shardSyncStrategyType` is set to `ShardSyncStrategyType.SHARD_END`, `PeriodicShardSyncManager#leasesRecoveryAuditorInconsistencyConfidenceThreshold` will be used to determine the threshold for number of consecutive scans containing holes in the lease table after which to enforce a shard sync. When `KinesisClientLibConfiguration#shardSyncStrategyType` is set to `ShardSyncStrategyType.PERIODIC`, `leasesRecoveryAuditorInconsistencyConfidenceThreshold` is ignored.
* New configuration options are available to configure `PeriodicShardSyncManager` in `KinesisClientLibConfiguration`
| leasesRecoveryAuditorInconsistencyConfidenceThreshold | 3 | Confidence threshold for the periodic auditor job to determine if leases for a stream in the lease table is inconsistent. If the auditor finds same set of inconsistencies consecutively for a stream for this many times, then it would trigger a shard sync. Only used for `ShardSyncStrategyType.SHARD_END`. |
* New CloudWatch metrics are also now emitted to monitor the health of `PeriodicShardSyncManager`:
| NumStreamsWithPartialLeases | Number of streams that had holes in their hash ranges. |
| NumStreamsToSync | Number of streams which underwent a full shard sync. |
* Introducing deferred lease cleanup. Leases will be deleted asynchronously by `LeaseCleanupManager` upon reaching `SHARD_END`, when a shard has either expired past the stream’s retention period or been closed as the result of a resharding operation.
* New configuration options are available to configure `LeaseCleanupManager`.
| leaseCleanupIntervalMillis | 1 minute | Interval at which to run lease cleanup thread. |
| completedLeaseCleanupIntervalMillis | 5 minutes | Interval at which to check if a lease is completed or not. |
| garbageLeaseCleanupIntervalMillis | 30 minutes | Interval at which to check if a lease is garbage (i.e trimmed past the stream's retention period) or not. |
* Including an optimization to `KinesisShardSyncer` to only create leases for one layer of shards.
* Changing default shard prioritization strategy to be `NoOpShardPrioritization` to allow prioritization of completed shards. Customers who are upgrading to this version and are reading from `TRIM_HORIZON` should continue using `ParentsFirstShardPrioritization` while upgrading.
* Introducing a validation step to verify if ShardEnd is reached, to prevent shard consumer stuck scenarios in the event of malformed response from service.
* Introducing support for ListShards API. This API is used in place of DescribeStream API to provide more throughput during ShardSyncTask. Please consult the [AWS Documentation for ListShards](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_ListShards.html) for more information.
* Added configuration parameters for ListShards usage
| Name | Default | Description |
| ---- | ------- | ----------- |
| [listShardsBackoffTimeInMillis](https://github.com/awslabs/amazon-kinesis-client/blob/3ae916c5fcdccd6b835c86ba7f6f53dd5b4c8b04/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1412) | 1500 ms | This is the default backoff time between 2 ListShards calls when throttled. |
| [listShardsRetryAttempts](https://github.com/awslabs/amazon-kinesis-client/blob/3ae916c5fcdccd6b835c86ba7f6f53dd5b4c8b04/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1423) | 50 | This is the maximum number of times the KinesisProxy will retry to make ListShards calls on being throttled. |
* Updating the version of AWS Java SDK to 1.11.272.
* Deprecated certain [KinesisProxy](https://github.com/awslabs/amazon-kinesis-client/blob/3ae916c5fcdccd6b835c86ba7f6f53dd5b4c8b04/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java) constructors.
* Allow disabling check for the case where a child shard has an open parent shard.
There is a race condition where it's possible for the a parent shard to appear open, while having child shards. This check can now be disabled by setting [`ignoreUnexpectedChildShards`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1037) to true.
Logging long running tasks can be enabled by setting the following configuration property:
| Name | Default | Description |
| ---- | ------- | ----------- |
| [`logWarningForTaskAfterMillis`](https://github.com/awslabs/amazon-kinesis-client/blob/3de901ea9327370ed732af86c4d4999c8d99541c/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1367) | Not set | Milliseconds after which the logger will log a warning message for the long running task |
Added better handling of DynamoDB failures when updating leases. These failures would occur when a request to DynamoDB appeared to fail, but was actually successful.
Prefetching will retrieve and queue additional records from Kinesis while the application is processing existing records.
Prefetching can be enabled by setting [`dataFetchingStrategy`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1317) to `PREFETCH_CACHED`. Once enabled an additional fetching thread will be started to retrieve records from Kinesis. Retrieved records will be held in a queue until the application is ready to process them.
Pre-fetching supports the following configuration values:
| Name | Default | Description |
| ---- | ------- | ----------- |
| [`dataFetchingStrategy`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1317) | `DEFAULT` | Which data fetching strategy to use |
| [`maxPendingProcessRecordsInput`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1296) | 3 | The maximum number of process records input that can be queued |
| [`maxCacheByteSize`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1307) | 8 MiB | The maximum number of bytes that can be queued |
| [`maxRecordsCount`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1326) | 30,000 | The maximum number of records that can be queued |
| [`idleMillisBetweenCalls`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1353) | 1,500 ms | The amount of time to wait between calls to Kinesis |
* Only advance the shard iterator for the accepted response.
This fixes a race condition in the `KinesisDataFetcher` when it's being used to make asynchronous requests. The shard iterator is now only advanced when the retriever calls `DataFetcherResult#accept()`.
* Call shutdown on the retriever when the record processor is being shutdown
This fixes a bug that could leak threads if using the [`AsynchronousGetRecordsRetrievalStrategy`](https://github.com/awslabs/amazon-kinesis-client/blob/9a82b6bd05b3c9c5f8581af007141fa6d5f0fc4e/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/AsynchronousGetRecordsRetrievalStrategy.java#L42) is being used.
The asynchronous retriever is only used when [`KinesisClientLibConfiguration#retryGetRecordsInSeconds`](https://github.com/awslabs/amazon-kinesis-client/blob/01d2688bc6e68fd3fe5cb698cb65299d67ac930d/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L227), and [`KinesisClientLibConfiguration#maxGetRecordsThreadPool`](https://github.com/awslabs/amazon-kinesis-client/blob/01d2688bc6e68fd3fe5cb698cb65299d67ac930d/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L230) are set.
Applications can now set a pending checkpoint, before completing the checkpoint operation. Once the application has completed its checkpoint steps, the final checkpoint will clear the pending checkpoint.
Should the checkpoint fail the attempted sequence number is provided in the [`InitializationInput#getPendingCheckpointSequenceNumber`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/types/InitializationInput.java#L81) otherwise the value will be null.
* Support timeouts, and retry for GetRecords calls.
Applications can now set timeouts for GetRecord calls to Kinesis. As part of setting the timeout, the application must also provide a thread pool size for concurrent requests.
When writes, or reads, to the lease table are throttled a warning will be emitted. If you're seeing this warning you should increase the IOPs for your lease table to prevent processing delays.
* Support configuring the graceful shutdown timeout for MultiLang Clients
This adds support for setting the timeout that the Java process will wait for the MutliLang client to complete graceful shutdown. The timeout can be configured by adding `shutdownGraceMillis` to the properties file set to the number of milliseconds to wait.
* Support timeouts for calls to the MultiLang Daemon
This adds support for setting a timeout when dispatching records to the client record processor. If the record processor doesn't respond within the timeout the parent Java process will be terminated. This is a temporary fix to handle cases where the KCL becomes blocked while waiting for a client record processor.
The timeout for the this can be set by adding `timeoutInSeconds = <timeout value>`. The default for this is no timeout.
__Setting this can cause the KCL to exit suddenly, before using this ensure that you have an automated restart for your application__
The MultiLangDaemon has been upgraded to use the v2 interfaces, which allows access to enhanced checkpointing, and more information during record processor initialization. The MultiLangDaemon clients must be updated before they can take advantage of these new features.
## Release 1.7.1 (November 3, 2016)
* General
* Allow disabling shard synchronization at startup.
* Applications can disable shard synchronization at startup. Disabling shard synchronization can application startup times for very large streams.
* Applications can now request a graceful shutdown, and record processors that implement the IShutdownNotificationAware will be given a chance to checkpoint before being shutdown.
* This adds a [new interface](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/interfaces/v2/IShutdownNotificationAware.java), and a [new method on Worker](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/Worker.java#L539).
* Add support for time based iterators ([See GetShardIterator Documentation](http://docs.aws.amazon.com/kinesis/latest/APIReference/API_GetShardIterator.html))
The `KinesisClientLibconfiguration` now supports providing a `ShardPrioritization` strategy. This strategy controls how the `Worker` determines which `ShardConsumer` to call next. This can improve processing for streams that split often, such as DynamoDB Streams.
* Remove direct dependency on `aws-java-sdk-core`, to allow independent versioning.
* Artifacts are now signed by the identity `Amazon Kinesis Tools <amazon-kinesis-tools@amazon.com>`
## Release 1.6.3 (May 12, 2016)
* Fix format exception caused by DEBUG log in LeaseTaker [Issue # 68](https://github.com/awslabs/amazon-kinesis-client/issues/68)
## Release 1.6.2 (March 23, 2016)
* Support for specifying max leases per worker and max leases to steal at a time.
* Support for specifying initial DynamoDB table read and write capacity.
* Support for parallel lease renewal.
* Support for graceful worker shutdown.
* Change DefaultCWMetricsPublisher log level to debug. [PR # 49](https://github.com/awslabs/amazon-kinesis-client/pull/49)
* Avoid NPE in MLD record processor shutdown if record processor was not initialized. [Issue # 29](https://github.com/awslabs/amazon-kinesis-client/issues/29)
## Release 1.6.1 (September 23, 2015)
* Expose [approximateArrivalTimestamp](http://docs.aws.amazon.com/kinesis/latest/APIReference/API_GetRecords.html) for Records in processRecords API call.
## Release 1.6.0 (July 31, 2015)
* Restores compatibility with [dynamodb-streams-kinesis-adapter](https://github.com/awslabs/dynamodb-streams-kinesis-adapter) (which was broken in 1.4.0).
## Release 1.5.1 (July 20, 2015)
* KCL maven artifact 1.5.0 does not work with JDK 7. This release addresses this issue.
* Support metrics level and dimension configurations to control CloudWatch metrics emitted by the KCL.
* Add new metrics that track time spent in record processor methods.
* Disable WorkerIdentifier dimension by default.
* **Exception Reporting** — Do not silently ignore exceptions in ShardConsumer.
* **AWS SDK Component Dependencies** — Depend only on AWS SDK components that are used.
## Release 1.4.0 (June 2, 2015)
* Integration with the **[Kinesis Producer Library (KPL)][kinesis-guide-kpl]**
* Automatically de-aggregate records put into the Kinesis stream using the KPL.
* Support checkpointing at the individual user record level when multiple user records are aggregated into one Kinesis record using the KPL.
See [Consumer De-aggregation with the KCL][kinesis-guide-consumer-deaggregation] for details.
## Release 1.3.0 (May 22, 2015)
* A new metric called "MillisBehindLatest", which tracks how far consumers are from real time, is now uploaded to CloudWatch.
## Release 1.2.1 (January 26, 2015)
* **MultiLangDaemon** — Changes to the MultiLangDaemon to make it easier to provide a custom worker.
## Release 1.2 (October 21, 2014)
* **Multi-Language Support** — Amazon KCL now supports implementing record processors in any language by communicating with the daemon over [STDIN and STDOUT][multi-lang-protocol]. Python developers can directly use the [Amazon Kinesis Client Library for Python][kclpy] to write their data processing applications.
## Release 1.1 (June 30, 2014)
* **Checkpointing at a specific sequence number** — The IRecordProcessorCheckpointer interface now supports checkpointing at a sequence number specified by the record processor.
* **Set region** — KinesisClientLibConfiguration now supports setting the region name to indicate the location of the Amazon Kinesis service. The Amazon DynamoDB table and Amazon CloudWatch metrics associated with your application will also use this region setting.
