Releases are made "when they're ready." It's very difficult to predict accurate release timelines as our developers are largely volunteers and it depends on the amount of time they are able to contribute in a given period.
A development timeline will be made available in the coming months to provide more guidance on our release plans.
We provide maintenance releases as needed, typically at least one maintenance release per every major stable release. We aim to provide a significant new stable release roughly every 18 months.
At this time our efforts are primarily focused on 2.1 development, though maintenance work on 2.0.x releases will be done as needed.
These are subject to significant change, and are simply a best guess estimate of one of the developers.
2.1 is rapidly progressing, and if all goes according to plan, it will be released sometime during the summer of 2013.