DeviceAuthenticationRegistrationStatus
data class DeviceAuthenticationRegistrationStatus(val authEpoch: Long, val authKeyInstalledAt: Instant)
The server's registration metadata of a device's authoritative device authentication key (docs/device-authentication-rotation.md), as returned by the signed GET /v1/devices/{user}/{device}/registration.
authEpoch is 1 after first registration and grows by one with every device recovery or routine rotation. authKeyInstalledAt is the server time at which the currently registered key was installed: first registration, the recovery or the rotation that installed it. Retries of those change neither. It is not the key's local creation time.