Due to the nature of ever-evolving virus threats, virus definitions are outdated within days of their release, necessitating some sort of a constantly updating definition system. The major antivirus companies have turned antivirus protection from a software to a service as a result. They do this by selling you “subscriptions” or “licenses” to use the software. This means that when your subscription is finished, you will stop getting updates. That is why it is so important to stay on top of your subscriptions and make sure they don’t run out.

From this comprehensive set of links below, you should be able to find the updates to the program you run on your computer. Some of the products can only be updated from within the program itself, meaning that you can’t download the definitions manually. I’ve made a note of those that are only updated manually.

Anti-Virus Updates