Just to play devils advocate, you could use both versioning schemes. For example, 13.01.24 could indicate it was the 24th revision of the 13.01 release (as opposed to being released on the 24th of the month).
In this context a revision is just a bug fix release, the same as a "point release" or "minor release" or "patch version." I'm sure there are terms I'm forgetting. A micro-version increment, where the system is ${major}.${minor}.${micro} (in what the kids call "semantic versioning," but what used to just be called "not versioning like an idiot.")
(i can never quite distinguish between revisions and releases... when is each used?)