### Recommended Upgrade for All Users of the 2.x Amazon Kinesis Client
**:warning: It's highly recommended for users of version 2.0 of the Amazon Kinesis Client to upgrade to version 2.0.3 or later. A [bug has been](https://github.com/awslabs/amazon-kinesis-client/issues/391) identified in versions prior to 2.0.3 that could cause records to be delivered to the wrong record processor.**
**:information_source: Amazon Kinesis Client versions 1.x are not impacted.**
* Provides an easy-to-use programming model for processing data using Amazon Kinesis
* Helps with scale-out and fault-tolerant processing
## Getting Started
1.**Sign up for AWS**— Before you begin, you need an AWS account. For more information about creating an AWS account and retrieving your AWS credentials, see [AWS Account and Credentials][docs-signup] in the AWS SDK for Java Developer Guide.
1.**Sign up for Amazon Kinesis**— Go to the Amazon Kinesis console to sign up for the service and create an Amazon Kinesis stream. For more information, see [Create an Amazon Kinesis Stream][kinesis-guide-create] in the Amazon Kinesis Developer Guide.
1.**Minimum requirements**— To use the Amazon Kinesis Client Library, you'll need **Java 1.8+**. For more information about Amazon Kinesis Client Library requirements, see [Before You Begin][kinesis-guide-begin] in the Amazon Kinesis Developer Guide.
1.**Using the Amazon Kinesis Client Library**— The best way to get familiar with the Amazon Kinesis Client Library is to read [Developing Record Consumer Applications][kinesis-guide-applications] in the Amazon Kinesis Developer Guide.
For producer-side developers using the **[Kinesis Producer Library (KPL)][kinesis-guide-kpl]**, the KCL integrates without additional effort. When the KCL retrieves an aggregated Amazon Kinesis record consisting of multiple KPL user records, it will automatically invoke the KPL to extract the individual user records before returning them to the user.
To make it easier for developers to write record processors in other languages, we have implemented a Java based daemon, called MultiLangDaemon that does all the heavy lifting. Our approach has the daemon spawn a sub-process, which in turn runs the record processor, which can be written in any language. The MultiLangDaemon process and the record processor sub-process communicate with each other over [STDIN and STDOUT using a defined protocol][multi-lang-protocol]. There will be a one to one correspondence amongst record processors, child processes, and shards. For Python developers specifically, we have abstracted these implementation details away and [expose an interface][kclpy] that enables you to focus on writing record processing logic in Python. This approach enables KCL to be language agnostic, while providing identical features and similar parallel processing model across all languages.
* Introducing support for processing multiple kinesis data streams with the same KCL 2.x for java consumer application
* To build a consumer application that can process multiple streams at the same time, you must implement a new
interface called MultistreamTracker (https://github.com/awslabs/amazon-kinesis-client/blob/0c5042dadf794fe988438436252a5a8fe70b6b0b/amazon-kinesis-client/src/main/java/software/amazon/kinesis/processor/MultiStreamTracker.java)
