That really depends on the viewpoint. The user-space APIs are stable and the Kernel project is going great lengths to ensure that userspace is never broken (any

That really depends on the viewpoint. The user-space APIs are stable and the Kernel project is going great lengths to ensure that userspace is never broken (any breakage is treated as a bug). So if you look at the userspace interface as the API semver would work against, we'd be at 1.0.1234 or something.