DOCSIS standards dictate that the service provider must distribute firmware updates to cable modem devices.  The end-user cannot simply install an update like most other network-enabled devices.

ARRIS develops the software update and makes it available to service providers.  The service providers qualify, test, and distribute the software update to devices on their network.  ARRIS has limited control or visibility on distribution by the service providers.

Please connect a computer directly to the SB8200 modem to isolate the issue and monitor the connection for 24 hours. Check if the internet connection still drops, and also see if the modem reboots on its own when the connection drops. Please check if there is a splitter on the coaxial connection.

If the internet connection drops I would suggested you to check the cable signal levels which should be in the acceptable range in order for the modem to work flawlessly. Cable modems rely on three main signal levels to function properly: Downstream Power Level, Upstream Power Level, and Signal-to-Noise Ratio (SNR). These levels determine the quality of your internet connection and can impact your browsing, streaming, and download speeds. 

To check the cable signal levels, please refer the below link where you can find the steps to check cable signal level.

http://arris.force.com/consumers/articles/General_FAQs/SB8200-Cable-Signal-Levels