Major Description
According to documentation Curator is compatible with ZooKeeper 3.5 and higher, but feature detection is based on the version of the ZooKeeper client shipped with Curator, not based on the actual version of the server the client is connected to. Ideally it should be based on both.
As ZooKeeper client is backward compatible with older servers (see https://zookeeper.apache.org/releases.html `ZooKeeper 3.9.x clients are compatible with 3.5.x, 3.6.x, 3.7.x and 3.8.x servers as long as you are not using new APIs not present these versions.`), applications using the zookeeper client will use a possibly more recent version for bugfix/security reasons while the server (which is not controlled by the application) may still be on an older version. This is a frequent scenario for application developed for Hadoop environment with Cloudera installations still based on ZK 3.5.5.
As a solution, it should be possible to instruct curator client/framework to specify a baseline zookeeper version (better would be to detect the remote version and adjust) and to disable unavailable features even if supported by the ZooKeeper client
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