Adding serialization support for APIP accessibility structures, along with capabilities for controlling the output XML namespaces via profiles. Sane ISO-compliant time input and output for audioFileInfo and videoFileInfo made possible by the addition of a dependency on joda-time.
Improving validation of content links. Firming up parent/child relationship typing for accessibility elements.
Adding stylesheet and apipAccessibility to the elements which now can contain these in QTI 2.1 Final: rubricBlock, templateBlock, feedbackBlock, and modalFeedback.