"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Leopard In Release Candidate Cycle, 9A559 Gallery
With only two known issues remaining, MacRumors sources are indicating that Leopard is in the release candidate stage of development. Release Candidates are typically chosen amongst builds that have no known major issues and little to no known minor issues. If thorough testing does not produce any show-stopping issue, a Gold Master will be declared and production of media and packaging will commence.
Production times for software can take 2-3 weeks, which means Apple has approximately 2 weeks left for testing of release candidates and certification of a gold master. Yesterday, MacScoop said their sources had indicated a final candidate was near.