Log into the router (usually 192.168.1.1 ), go to Status > Device Info . The hardware version is listed there.
There is a caveat. If your router was provided by your Internet Service Provider (ISP)—for example, MTNL, BSNL, or Airtel—it might be running a customized firmware. In this case, you should use the firmware from the generic D-Link website. Using generic firmware on an ISP-locked router can cause connection issues. d link model dsl 2750u firmware download