Flip the router over. Look for a sticker that says "Ver: 1.0" or "Ver: 2.0". You must match the firmware to this hardware version.
A critical vulnerability found in Tenda AC8 16.03.34.09 that affected the fromSetWirelessRepeat function in the /goform/WifiExtraSet file. By manipulating the wpapsk_crypto argument, attackers could launch remote stack-based buffer overflow attacks. The exploit has been publicly disclosed, increasing the risk for unpatched devices. tenda ac8 firmware