The latest firmware transforms the ZTE MC801A from a "good" router into an excellent one. If you bought the device at launch and haven't updated recently, you are missing out on significant performance gains, specifically regarding antenna support and thermal handling.
Some updates add support for WPA3 security or better management of connected devices. Method 1: Automatic Online Update (OTA) zte mc801a firmware update
If your router is locked to a specific carrier or does not find updates automatically, you may need to use a PC-based tool. The latest firmware transforms the ZTE MC801A from