Modem Question

Lately my modem has been dropping my connection and the wifi signal has gotten to the point where it is no longer stron upstairs.. When i first got the modem set up the signal was strong and i had no issues with it.. The modem has been in the same spot since i got it.. Its been about 8 years or more now so i figured the problems are because the modem is outdated.

I contacted xfinity and they told me what i thought and its the modems age causing the issues.. So they told me they would send me out a brand new updated modem.. Great , i thought the problems will be fixed after the new one arrives.. I got it today and they sent me the exact same modem ........ 

Why would they send me the exact same outdated modem that i have problems with already?

My question is , will the modem look the same but have up to date parts inside???

If its the same exact modem parts and all then im just sending it back.. 

Any info would be helpful, thanks in advance..