: Go to Management > System Management > Software Upgrade .
Most service providers (like Airtel, BSNL, or Totalplay) manage ZTE ONTs via a protocol called TR-069. This allows the ISP to push firmware updates automatically overnight. Zte F670 Firmware Update
Most users never update their router firmware. That is a mistake. For the ZTE F670, updates typically address: : Go to Management > System Management > Software Upgrade