I assume you mean numbers without dots rather than without digits.

I like the DNS convention and have used it elsewhere, but would miss the major/minor distinction for a module. I may not be good at it, but I like the idea of the major version number changing as the committed interface changes, or when incompatibilities are introduced. An API version number could be added as a prefix, maybe with an underbar for visual distinction. Perhaps something like: 'MM_YYYYMMDDXX'

Yet, floating point numbers with only a couple of digits after the decimal point seems to be the most common, among the few modules I have looked at. I'm more of a sheep than a wolf, nervous about doing something unconventional which may become an unfortunate edge case some day.

As an alternative to multiple dots in the extended version numbers, I have the impression that there is some special handling to preserve an underbar in the fractional part of a floating point version (e.g. "1.02_03"), but maybe this is only in version, and I don't understand why the example isn't "1.002_003".

Not that I'm pinning any of this on you - I appreciate your comments.