How Can I Tell If My Owned Panoramic Router Need an Update?

I have an Arris TG1682 Panoramic Gateway Router which I bought from Walmart about 4 years ago. Recently I have been having wifi connectivity issues in one room of my house. This is a new problem and it is usually happens on my phone, but sometimes my laptop. Besides the gateway router, I also have a range extender downstairs. The router is upstairs about 15 feet away from the room I am suddenly having trouble with. I chatted with support and I don't think the guy could understand what I was asking. He kept telling me to check my connection now - I was connected and speaking with him through chat!  I wanted to know if my router needed a firmware update. I was thinking maybe that could be why I was suddenly having connection issues.  I also had a question about the WiFi lights blinking all the time.  I wanted to know if that is normal.  Can anyone point me to the place on my computer where I can see if my firmware for the Arris needs updating?  Though I bought it at Walmart, Arris told me to contact Cox but Cox's rep doesn't understand what I am asking. Thanks!