We're primarily focused on 2.4 at the moment, with some effort going into 2.3.3 as needed to keep things polished up. The real driving factors for point releases are new hardware product requirements, severe bugs, security vulnerabilities, or when we reach a point where we feel like it's necessary.
The release of 2.4 will trail the FreeBSD 11 release but not by far, otherwise we don't have any estimates that I'm aware of for other versions. Support for 2.3.x will be continuing after 2.4 since 2.4 is dropping i386, so i386 boxes can stay on 2.3.x for a while until they're eventually phased out.
Assuming next pfSense release is around the corner. https://www.freebsd.org/releases/11.0R/announce.html YAY!