Hi Ro yea I received the same msg from xfinity my warranty is still good till 2024 so I called them and they tried to tell me some bull to call Arris they just want to pass the buck. also when I log into the router through my pc it's telling me my browser is outdated and I should use firefox so it's says I have to upgrade to version 63.0.3 or higher lol and it's already at version 107.0.1 i tried chrome and another browsers without any security Addons on turned off antiviruses malware ect ect still says the same no mater what browser I use says it's outdated so who know what the hel is up with the firmware in the router and at xfinity, the router was working fine I even adjusted the wifi Chanels for 2.4 and 5.0 all was good till last month, what I think is that i don't think they are pushing the updates for the router when they upgrade the system 3 times now I'm also getting between 450 to 500 mbps but was getting around 600 to 720 before my plan was 800 then they added to 900 now they added last week to 1GIG so I'm like WTH is going on here now on my xbox for example in getting lower than 400 mbps and my phone is even more screwed crazy !!

==========================

Here's my current specs on my SBG8300

HW version:6

Boot Version CGM2.86C.573854.R.1808221028

CORE VERSION 0.0.0.0

MODEL SBG8300

FLASH PART 470MB

DOWNLOAD VERSION 01.02.078.04.NCS

SERIAL NUMBER BY REQUEST OF HELP DESK if you need it please send me a request or look into my account.

DOCSIS 3.1

Also at LOGIN PAGE SOFTWARE IMAGE Name: says.

AR01.02.078.092820_711.NCS.10

Just purchased last year to get my own Modem to save the 17 bucks a month figures would save in the long run, it ran great before they started doing upgrades they are still using Docsis3.1 so I don't understand and i know the router can handle the speed youll never get 1 GIG of course but 380 is like really messed up also now you can't even find it in their compatability list on the xfinity site they took it out wth i hope Arris support can help me out and hopefully i helped some users here with similar this similar problem I retired from internet security for the Mil so I kinda know enough to be dangerous lol hehe thanks hope this helps

….Merry Christmas Happy New Years Happy Holidays to all.

JT

New Jersey USA

That’s interesting Xfinity would email you about SBG8300 no longer compatible.  Their website still showing the SBG8300 compatible with 800 Mbps speed for my area. 
 

Is your area different?  
 

http://mydeviceinfo.xfinity.com

Xfinity states it’s not compatible, I’m not getting the speeds I should be getting 500, not 800) and the modem isn’t on the list of compatible modems on Xfinity’s site for me. I’m in Indiana, that’s so strange that they would have it as a compatible modem for you but not for me.