Downgrade logback version and prepare for release 2.2.1

Author: vincentvilo-aws

README.md

@@ -196,7 +196,11 @@ all languages.
 * The [Amazon Kinesis Forum][kinesis-forum]
 
 ## Release Notes
-### Release 2.2.0 (2025-03-12) - IMPORTANT: See section ``Migration to Ruby KCL 2.2.0`` to ensure upgrading does not break compatibility
+### Release 2.2.1 (March 25, 2025)
+* Downgrade logback from 1.5.16 to 1.3.15 to maintain JDK 8 compatability
+
+### Release 2.2.0 (March 12, 2025) - IMPORTANT: See section ``Migration to Ruby KCL 2.2.0`` to ensure upgrading does not break compatibility
+#### :warning: [BREAKING CHANGES] - Release 2.2.0 contains a dependency version that is not compatible with JDK 8. Please upgrade to a later version if your KCL application requires JDK 8.
 * [#1444](https://github.com/awslabs/amazon-kinesis-client/pull/1444) Fully remove dependency on the AWS SDK for Java 1.x which will reach [end-of-support by December 31st, 2025](https://aws.amazon.com/blogs/developer/announcing-end-of-support-for-aws-sdk-for-java-v1-x-on-december-31-2025/).
   * The Glue Schema Registry integration functionality no longer depends on AWS SDK for Java 1.x. Previously, it required this as a transient dependency.
   * Multilangdaemon has been upgraded to use AWS SDK for Java 2.x. It no longer depends on AWS SDK for Java 1.x.

VERSION

@@ -1 +1 @@
-2.2.0
+2.2.1

pom.xml

@@ -8,7 +8,7 @@
         <netty.version>4.1.118.Final</netty.version>
         <netty-reactive.version>2.0.6</netty-reactive.version>
         <fasterxml-jackson.version>2.13.5</fasterxml-jackson.version>
-        <logback.version>1.5.16</logback.version>
+        <logback.version>1.3.15</logback.version>
     </properties>
     <dependencies>
         <dependency>