Looks like there may possibly be a Jena 1.6 before 2.0. Mainly bug fixes but also:
Jena-Sesame integration (http://sesame.aidministrator.nl/ - Sesame is an Open Source RDF Schema-based Repository and Querying facility)
N3 Reader - It runs at about 19K statements/s (it is I/O bound in the lexer - optimization makes no difference) parsing, 9K triples/s generating RDF.
Original 1.6 email