Releases are sequential. Normally each release is about 2 months in duration. 3.4 will be longer due to holidays (~3 months)
We only firm the scope of the next release - then publish it here: http://help.wildapricot.com/display/DOC/Release+history
So yes, potentially it might be as much as a year.
Generally speaking, roadmap forum contains all the items we are targeting to address in the next 12 months - so we update it after each release.
Dmitry Buterin, Chief Apricot