Read below and answer: So which is the source of truth ? Is 0.10.2.0 compatible to 0.10.0 or 0.10.1?
Which site needs correction? From current Kafka docs. Statement from Kafka site: https://kafka.apache.org/documentation/#upgrade Starting with version 0.10.2, Java clients (producer and consumer) have acquired the ability to communicate with older brokers. Version 0.10.2 clients can talk to version 0.10.0 or newer brokers. However, if your brokers are older than 0.10.0, you must upgrade all the brokers in the Kafka cluster before upgrading your clients. Version 0.10.2 brokers support 0.8.x and newer clients. Before 0.10.2, Kafka is backward compatible, which means that clients from Kafka 0.8.x releases (CP 1.0.x) will work with brokers from Kafka 0.9.x, 0.10.0, 0.10.1 and 0.10.2 releases (CP 2.0.x, 3.0.x, 3.1.x and 3.2.x), but not vice-versa. This means you always need to plan upgrades such that all brokers are upgraded before clients. Hmm...do some more reading and research on Confluent site found this which seems to contradict the above statement: http://docs.confluent.io/3.2.0/streams/upgrade-guide.html Upgrading from CP 3.1.x (Kafka 0.10.1.x-cp2) to CP 3.2.0 (Kafka 0.10.2.0-cp1) Compatibility Kafka Streams applications built with CP 3.2.0 (Kafka 0.10.2.0-cp1) are forward and backward compatible with certain Kafka clusters. Compatibility Matrix: Kafka Broker (columns) Streams API (rows) 3.0.x / 0.10.0.x 3.1.x / 0.10.1.x 3.2.0 / 0.10.2.0 3.0.x / 0.10.0.x compatible compatible compatible 3.1.x / 0.10.1.x compatible compatible 3.2.0 / 0.10.2.0 compatible compatible EMPHASIS ON CONTRADICTION BELOW from site desciption: Backward-compatible to CP 3.1.x clusters (Kafka 0.10.1.x-cp2): This is the first release allowing to upgrade your Kafka Streams application without a broker upgrade. New Kafka Streams applications built with CP 3.2.0 (Kafka 0.10.2.x-cp1) will work with older Kafka clusters running CP 3.1.x (Kafka 0.10.1.x-cp2). Kafka clusters running CP 3.0.x (Kafka 0.10.0.x-cp1) are not compatible with new CP 3.2.0 Kafka Streams applications though. -Roger
