Yes, Java driver 4 is not binary-compatible with older versions. Our recommendation is that you upgrade to the latest version instead of re-coding your app for an older version. If you run into issues with the older version, you will have to upgrade anyway to get the fix. Java driver v3.4 was released in January 2018 so it's very old.
See the upgrade guide here -- https://docs.datastax.com/en/developer/java-driver/4.9/. Cheers! >
