I think you need to reset the router back to factory settings and reenter your settings. I also power the router off, wait 20, and power on after making changes.

1.0.7 Build 20180425 rel.62587 is the same as Archer C7(EU)_V4_180425. (it is the date of the firmware) I know... I had the same question and TP-Link answered it for me...

Can you move the router next to the modem and still get the WIFI coverage you need? If not maybe an extender or mesh is in order to extend the WIFI signal.

Your post for the same issue has replies. Did they not help?

I assume you are replacing just a router and not a Gateway device which is a modem/router combo. If you have a gateway, you will also need a Modem. An AC router would be an improvement. As to one...

You sign on to the router using your PC using a browser such as Firefox, chrome, Safari, Explorer, ... which is connected to your router. Once signed on, there will be options for changing the WIFI...