New box for DVR service

Might be a silly question but if I upgraded my service to have DVR (never had it before) should I have gotten a new cable box for my main TV?  I went into an xfinity store to exchange my second/bedroom cake box that wasn't working.  I inquired about getting internet service and DVR.  I upgraded to have both.  I was given the large modem/router for the internet and a new box for my bedroom along with one new remote.  I was not given a new box for the living room.  The box I have is several years old.  I was given no instructions other than to download the app.  The app recognizes a new second box but of course the main box is the same one.