The Plus driver looked the newest firmware up in Netgear's download
catalogue and named firmware_update_available itself. It now reports
get_firmware_offer() (napalm-device-types 4.16 FirmwareOfferMixin): what
runs, the newest offered, whether that is newer by Netgear's versioning,
and the download link; netOrk names the warning (netOrk #1111). The Smart
driver's empty get_device_warnings goes too. Requires
napalm-device-types 4.16.0.