This package is for ALL versions of HDFS protocols that use writable data types and are compatible with the version of the protocol that was shipped with Release 23 of Hadoop.

Compatibility should be maintained:

You can add new methods and new types. If you need to change a method's signature, please add a new method instead. When you add new methods and new types do NOT change the version number.

Version number is changed ONLY when compatibility is broken (which should be very rare and a big deal).