Servicing Telemetry / Version Upgrade
Air-gapped / never-connect, never-transfer networks are left with no method to perform any upgrades due to the requirement to submit telemetry data. The offline servicing method is not a valid method to perform these actions due to security regulations. No amount of assurances from the Microsoft team about the content of files will suffice.
Telemetry data would have to be plain-text, human-readable, and of an appropriate size to allow manual transcribing to permit this methodology to work. Even then, some information which Microsoft may seem as innocent / standard is likely to prevent export on some networks due to various regulations.
Current answer from technical support is to stand up a completely new environment/site and migrate to it, which is obviously a less than desirable approach.
Recommend that Microsoft restores the ability to use full baseline media to perform system upgrades or provide a path for professional services to generate a 'generic' telemetry file to facilitate upgrades on highly secure environments.