Thanks; I'm not sure in that case saying 1.x is guaranteed to not break things is very useful at all. Systemd (as far as I know) follows semantic versioning, but their version number is up in the hundreds. Without some sort of guess at how long a release might last, 2.0 might as well ship the minute after 1.0 ships. (Okay, probably not...)
The core team has reserved the right to break backcompat without changing the major version if they find a serious problem in 1.x series. So I expect that it will be a while (at least a few years) before 2.0 is created.
