Panther Server 7B33
Panther Server build 7B33 was released to developers. (7B32 was recently seeded internally)
Apple remains vague in the details of the improvements but simply states that "this release reflects extensive engineering efforts since the last seed".
Apple's website provides a Panther Server Sneak Preview which details the improvements that the Server version of Panther will provide.
Recent rumors have placed the release of (non-server) Panther in September. Hints have suggested that Panther Server will follow shortly.