As part of #2688479: Replace update status XML with a more modern system, I’d like to see if we can remove the <version_major>, <version_minor>, <version_patch>, and <version_extra> tags from update status XML. These version number components are redundant with <version>.
packages.drupal.org treats 8.x-1.2 as major = 1, minor = 2. Update status XML omits version_minor and version_patch = 2. To support semantic versioning for contrib, #2681459: Add support for optional contrib semver-ish tags and releases to d.o, we might want to migrate version_patch → version_minor, so this lines up all the way down.