Changes from 6.0.x to 6.5
REST API Changes
Several objects got additional attributes and sub-elements (e.g. "startDate" in reference to a build, "personal" in a change). Please check that your parsing code still works.
Changes from 6.0.1 to 6.0.2
Maven and XML Test Reporting Load CPU on Agent
If you use Maven or XML test reporter and your build is CPU-intensive, you might find important the known issue. Patch is available, fixed in the following updates.