We've found an issue with the migration tool used to migrate users from
version 2 of ZooKeeper to version 3. This tool was provided to users who
upgraded from the SourceForge v2 ZK, after we moved to being a
subproject of Apache Hadoop (which is the same time that we incremented
the version number from 2.x.y to 3.0.0 - 2+ years ago)
Please note, this only effects users who migrated their ZK data
directory from version 2 to version 3. If you have only ever used ZK
version 3.0.0 and later this does not effect you.