Nginx doesn’t use SemVer but still does Odd-Even Versioning: odd-numbered releases are “development” and even-numbered are “LTS”. The significance of this release is that there is now a new stable LTS version that includes everything from the latest development branch.

Linux and GNOME used to do Odd-Even Versioning, but stopped many years ago. Other big projects that still do this are Node (major versions) and RHEL (minor versions).