In some of their responses, they claim they check for a Google-certified OS for security reasons. Can't be true, because they're permitting an OS which hasn't received security patches for the past 8 years. They're disallowing a much more secure OS than anything Google approved.
Banning a more secure operating system as part of implementing a fake security feature shows serious anti-security culture at RevolutApp. A company which deliberately permits a device with no patches for 8 years but not a hardened OS does not understand or care about security.