We have the same problem and have 60 licenses that expire in January 2017. >:(
https://www.avast.com/faq.php?article=AVKB231#idt_500
"Can I use Avast Endpoint Security with Windows 10?
The Avast Endpoint Protection products are being updated for Windows 10 compatibility and should be available in Autumn 2015. We recommend that customers who require Avast Endpoint Security delay upgrading to Windows 10 until the compatible version of the product is available."
Nope: autumn is usually considered to start with the September equinox and end with the winter solstice (21 or 22 December) (see https://en.wikipedia.org/wiki/Autumn).
Anyway, considering the Avast’s unacceptable delays, I don’t think we will have a working version before 2016.
I am also looking for answers on the availability of an Avast Endpoint Protection suite for Windows 10. We are starting to deploy Windows 10 and wish to use Avast but have some tough questions to answer. What are the risks of using Avast Free vs. Endpoint Protection Suite?
Having 65 licences I’ll probably buy some other product next time unfortunately. Beside compatibility issues with Windows 10 there were also some false positives that came just at the worst possible moment when our production was full 24/7 and we were unable to work on some computers.
We are coming in December, and no one position my friends :-X :-\