If your router says "No updates available" but you know a newer version exists (from forums like 4G Australia or Reddit), try changing your DNS to 8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) and reboot. This sometimes bypasses carrier update gateways.
Specific firmware used by Nordic providers, sometimes cited in vulnerability databases like CVE Details for security monitoring. How to Update Web Admin Interface of the ZTE MC801A 5G Router 22-Mar-2022 — zte mc801a firmware