Apache JackRabbit 1.6.x is claimed to be backwards compatible with previous version. That is not the case and it appears to be leading to severe data corruption issues in our production environment. Specifically, in previous versions of JackRabbit, jcr:isCheckedOut is declared mix:versionable. In the new version it is declared mix:simpleVersionable.

The problem results in some warnings similar to the following:

ItemManager - property at /path/to/node/jcr:isCheckedOut has invalid definitionId (1284956073)

However, it appears to cause activation/deactivation to fail and in at least one case, an activation caused corrupt data to be deployed to the production public instances of our environment causing the entire repository workspace to become corrupt.

The JackRabbit bug has just been declared resolved here (#JCR-2433) https://issues.apache.org/jira/browse/JCR-2433