Downgrade Confluent version due to license issues

build/cqs.tsv

@@ -263,8 +263,8 @@ ch.qos.reload4j:reload4j	1.2.25	provided
 com.amazonaws:aws-java-sdk-s3	1.12.625	provided
 com.datastax.cassandra:cassandra-driver-core	3.11.5	provided
 com.datastax.cassandra:cassandra-driver-mapping	3.11.5	provided
-io.confluent:kafka-avro-serializer	7.6.0	provided
-io.confluent:kafka-schema-registry-client	7.6.0	provided
+io.confluent:kafka-avro-serializer	6.2.9	provided
+io.confluent:kafka-schema-registry-client	6.2.9	provided
 javax.media:jai_core	1.1.3	provided
 org.apache.accumulo:accumulo-start	2.1.2	provided
 org.apache.commons:commons-text	1.10.0	provided

docs/user/upgrade.rst

@@ -158,7 +158,7 @@ The following dependencies have been upgraded:
 * commons-lang3 ``3.8.1`` -> ``3.14.0``
 * commons-pool2 ``2.6.1`` -> ``2.12.0``
 * commons-text ``1.10.0`` -> ``1.11.0``
-* confluent ``6.2.7`` -> ``7.6.0``
+* confluent ``6.2.7`` -> ``6.2.9``
 * cqengine ``3.0.0`` -> ``3.6.0``
 * org.apache.curator ``4.3.0`` -> ``5.6.0``
 * geotools ``28.2`` -> ``30.2``

pom.xml

@@ -135,7 +135,7 @@
         <protobuf.version>2.5.0</protobuf.version> <!-- see also confluent.protobuf.version-->
         <cassandra.version>3.11.5</cassandra.version>
         <kafka.version>3.7.0</kafka.version> <!-- needs to align with confluent version -->
-        <confluent.version>7.6.0</confluent.version> <!-- corresponds to kafka 3.6 -->
+        <confluent.version>6.2.9</confluent.version> <!-- corresponds to kafka 2.8 - newer versions have license issues, see https://gitlab.eclipse.org/eclipsefdn/emo-team/iplab/-/issues/13628 -->
         <confluent.protobuf.version>3.19.6</confluent.protobuf.version>
         <sedona.version>1.5.0</sedona.version>
         <sedona.spark.version>3.4</sedona.spark.version>