- 20.04: a typical upstream release in April 2020
- 20.04.2: additional releases within the same month add a counter
- 20.04.10: rarely, maintenance upstream releases for older LTSP versions may be needed when grave bugs are backported or security issues are discovered; since these will be kept in separate repositories, they can just bump that month's counter, or use "+"
Distribution package versioning should be separated with a hyphen "-" or tilde "~":
- 20.04-3: the third Debian packaging of the 20.04 release
- 20.04-3ubuntu1: an Ubuntu-patched version of the aforementioned Debian package
- 20.04-1~ubuntu20.04.1: an LTSP stable PPA build; debian/changelog contains the released version
- 20.04-1+ubuntu20.04.1: an LTSP proposed PPA build; debian/changelog contains the older version
Note: the YYYY.MM scheme was also considered, but it's longer, and YY.MM can easily be upgraded to YYYY.MM or to YYMM, but not the opposite.