Yes, as you can see on the API page you linked encryptedValues is available only on macOS 12+ and iOS 15+. This is a huge problem for us because B2 actually supports macOS 10.15+ and iOS 14+ so we can’t support this API without dropping a considerable portion of users currently using B1.
Usually, we can check inside the code the OS version the user is running and eventually enable a version-specific API but this is different because we are not aware of the other user devices and which OS they are running. Otherwise, we can find ourselves in situations where some user devices can’t sync.