Announcing ksqlDB 0.21.0

The latest release of ksqlDB 0.21.0 includes significant upgrades to its foreign-key joins, the introduction of the BYTES data type, and a new ARRAY_CONCAT function. With these enhancements, developers can now use arbitrary expressions to define foreign keys, handle binary data, and concatenate arrays in a more flexible way. The new features are now available in Confluent Cloud and can be accessed via the standalone distribution or with Confluent. Additionally, ksqlDB is part of a broader effort to enhance stateful processing capabilities through versioned key-value stores, which allow users to store multiple record versions per key.