Version Numbers are simple dates.

They are one 8 digit number representing the year, month and day.

For example.

20030523 is 23rd of May 2003.

Sometimes they end in a v2 v3 v4 etc, indicating they have been bug fixed and re released but are still the same release.

Sometimes I get over the top and add hours minutes and even seconds onto the end but a day resolution seems reasonable enough.