Mike Boylan on Twitter points to this new Apple Support article on re-installing your Mac. The option for restoring from internet recovery have changed:
Reinstall the latest macOS that was installed on your Mac, without upgrading to a later version.1
Upgrade to the latest macOS that is compatible with your Mac.2
Requires macOS Sierra 10.12.4 or later. Reinstall the macOS that came with your Mac, or the version closest to it that is still available.