It is common to provide a separate API address after a breaking changes update. This prevents current clients not to get broken as these may not support these changes.
Seems the purpose is to prevent breakage - i.e. that the "not" in second sentence of the paragraph should be removed.
§ 4.4
Api versions
contains this:Seems the purpose is to prevent breakage - i.e. that the "not" in second sentence of the paragraph should be removed.