The most reliable method. Many ISPs lock firmware updates to their infrastructure. Log into your ISP account → “Support” → “Router Firmware”. Search for “ZXHN H168N”.
The ZTE ZXHN H168N V2.2 is a highly distributed ADSL/VDSL modem-router, primarily deployed by Internet Service Providers (ISPs) across Europe, the Middle East, and Asia.
The Problem: Most of these devices are not "retail" units. They are custom-branded for ISPs (e.g., Movistar, Telenor, specific local providers).
If you want, I can: