Over-the-air (OTA) update: The phone can receive firmware updates over-the-air, which means that the update is downloaded and installed directly on the device. To check for OTA updates, go to Settings > About phone > System updates.
ZTE website: Users can download the firmware from the ZTE website and install it manually using a computer and a USB cable.
Recovery mode: Users can also update the firmware using recovery mode, which involves booting the phone into a special mode and installing the update from a file.