Netgear Nighthawk AC1900, Model C7000

I was recently informed by Comcast that my Nighthawk AC1900, Model C7000, purchased in 2016 is no longer compatible.  I called them but of course they were of no help.  I went to many stores to purchase the upgraded version of the Nighthawk but the same box and info appeared.  How can I tell if the modem in stock at stores is the same one I purchased in 2016?  In the meantime, Comcast talked me into getting their modem until I can figure out the problem.  Is my modem not working because I am still using Windows 10 instead of 11?  Any suggestions would be appreciated.