The ZTE F680, like many ONTs, is a constant target for botnets and hackers. Older firmware versions are vulnerable to known exploits (e.g., CVE-2018-14834, credential leaks, or backdoor accounts). A firmware upgrade closes these holes, preventing your ONT from becoming a zombie in a DDoS attack.
There are two primary methods for upgrading the ZTE F680: zte f680 firmware upgrade
Sometimes, your ISP pushes a firmware upgrade to align with new backend infrastructure (e.g., switching from IPv4 to IPv6 or updating VLAN tagging protocols). If you refuse the upgrade (or block it), you may lose connectivity entirely. The ZTE F680, like many ONTs, is a