@Dr_Dunot 

The version is determined by the hardware revision.  So you wouldn't be able to update that part.  The build and revision are the Firmware details.  Normally a router update is on our website, however Cable devices were and are different.  With these devices updates are regulated through cable companies and can only be updated by your ISP through an update push from the ISP through the cable line. You can reach out to your ISP and ask them to push an update request, though you may get a uniformed level 1 agent who tells you that they can't do this because its not their device.  This is 100% inaccurate and you may need to contact a level 2 or 3 tech there to get someone who knows what they are doing.  Still you may already be on the latest frimware.  FW support typically ends once a product is End of Life, unless its a security or major bug being addressed.