system
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Here is what I found from researching avast site: http://www.avast.com/en-us/store and click schools.
Note what it says:
avast! Free Antivirus:
The world’s most popular antivirus, previously free only for home use, is now FREE also to educational institutions. For standalone (non-centrally managed) endpoints. Then it shows “download” and goes back to same link for avast free.
avast! Endpoint Protection Suite
Our centrally managed award-winning IT-security software for business networks is now FREE to educational institutions. Divert your IT-security budget somewhere else! Then it shows “Apply”.
See the difference.
I am not sure if I interpreted it correctly.