For example, a 12.1.2.0.2 extend client can connect to a 12.1.2.0.1 proxy. That is, extend clients can connect to cluster proxies that have lower or higher version numbers. Starting with version 12.1.2.0.1, extend clients support both forward and backward compatibility with cluster proxies. That is, extend clients can connect to cluster proxies that have either the same or higher second digit of a major release. Prior to version 12.1.2.0.1, extend clients only support forward compatibility with cluster proxies.
Compatibility requires the use of POF, because POF can support backward compatible serialization changes.
