No further security updates will be provided per Symantec's maintenance agreement.
If you use Symantec Anti Virus Corporate Edition 10.x or Symantec Client Security 3.x, read the document Updating virus definitions for Symantec Anti Virus Corporate Edition 10.x and Symantec Client Security 3.x.
The server gets definitions updates using Live Update or an file, and then automatically distributes the definitions to each of its clients on the network.
Read the document How to use Live Update is a program that connects to a server, downloads the latest definitions, and applies the definitions to the computer on which it is running.
You can run Live Update from Symantec System Center, or within Symantec Anti Virus.
For the correct procedures, read the document How to update virus definitions for Norton Anti Virus Corporate Edition.This batch file automatically downloads and extracts the latest file from a statically named executable (Navup8.exe), and copies the file to the appropriate location.For more information, read the document How to automatically update Symantec Anti Virus Corporate Edition 8.x definitions without using Live Update.You can also copy an file from the \SAV folder on any Symantec Anti Virus server.The modified date of the file matches the date of the virus definitions. EXE checks for new files, and then initiates the update process. EXE checks for new files about every 10 minutes by default.