A new stable OpenOffice.org version has been released a few days ago (29 March).
I ran the JODConverter 2.1.1 test suite against the new OpenOffice.org 2.2 and as expected there are no incompatibilities - all tests are successful.
From the OpenOffice.org press release and release notes, the main changes related to conversion capabilities seems to be:
Warning! Update: there is actually a bug in OpenOffice.org 2.2 that affects StreamOpenOfficeDocumentConverter: conversions from a few formats including Word and Excel don't work any more. The default filed-based converter is not affected.
Please vote for the issue to encourage the OpenOffice.org team to fix the problem.