The page https://tracker.pureos.net/w/development/packaging_overview/ documents how to add a _higher_ number when forking from Debian.
Apparently that is a strict rule.
Please expand those guidelines/rules to permit the existence of the "~" for Debian-based package versioning, used in situations where important to stay _below_ a certain other version.
What is the use case for explicitly staying below a Debian revision? This may break quite a few assumptions and no Debian derivative (that I know of) does this.
Higher-than-Debian version shadows a Debian package if both are available. That is suitable for packages deliberately deviating from its Debian counterpart.
Example: debian-games (we fix an FSF-specific freedom-issue)
Lower-than-Debian version lets a Debian package shadow it if both are available. That is suitable for packages introduced only as an interim until availability of its Debian counterpart.
Example: matrix-mirage targeted byzantium (simple rebuild until available via Debian testing)
Lower-than-both-Debian-and-another version lets either Debian or another of our packages shadow it if any of those others are available. That is suitable for packages existing only as an interim until availability of either that other or the Debian counterparts.
Example: matrix-mirage targeted byzantium (simple rebuild until available via either byzantium or Debian testing)
The idea of "shadowing" upstream or downstream as the case may be seems pretty useful though my brain is more accustomed to having the PureOS version of a package be higher.