Want to upgrade Cassandra from 3.3 to 4.0.6. The database is used by Java applications that are running the Datastax driver 3.2 and some using the Dropwizard cassandra driver version 4.0.
Will I have to update the Java applications as part of the upgrade ? Or is Cassandra 4.0.6 backward compatible ?
Cassandra 4.0 is backwards compatible with older protocol versions (3 and 4). If you were able to connect to a Cassandra cluster running 3.X with your application, you should be able to connect to a 4.0 cluster. As long as you are using some version of datastax java-driver 3.0 or later, you should be able to continue using the same versions of client libraries you are already using.
That being said, 3.2 is a fairly old version. You may what to consider upgrading to the latest 3.X datastax java driver or look at the 4.X java driver (which is a complete rewrite and would require more code changes).
