ZTE does not provide a single universal firmware file. The correct update depends on your carrier/region (e.g., AT&T, Telstra, T-Mobile, Smart, Vodafone) and hardware version (MF920U is typically v1.0 or v2.0).
Confirm your specific model variant. The ZTE MF920 line includes variations like the MF920V, MF920W, and MF920U. Firmware files are not interchangeable. zte mf920u firmware update
Running the latest official firmware protects your device and improves your connection quality. ZTE does not provide a single universal firmware file