For providing better long-term support and communication, OpenSwoole Group has investigated the two most common versioning schemes—SemVer (semantic versioning) and CalVer (calendar versioning). OpenSwoole will use a kink of CalVer and respect SemVer.
SemVer is the most widely-used versioning scheme, so developers know they can upgrade minor versions without breaking anything. There are incompatible API changes when upgrading the MAJOR version.
"CalVer is a versioning convention based on your project's release calendar, instead of arbitrary numbers." - Calver.org
You can quickly spot if the library or software is outdated and how old the software version is from the version number. You can also see the release time of future versions.
"C language" uses Calendar Versioning such as C89, C99, C11. The well knows "Microsoft Windows" also uses Calendar Versioning systems, such as 95, 98, 2000. The other software using Calendar Versioning: