For clarity the build numbers for the Avast for Business anti-malware client and our Consumer client may not match when fully updated.
While Avast for Business is built off our consumer engine, it's not necessarily running the latest consumer codebase as soon as it releases since we have different requirements for business needs, and we have unique features as well (like Cloud management).
For the moment, I personally recommend against attempting to use any anti-malware engine with Windows 10 preview as I've seen many issues with many products - similar to those expressed here.
Don't worry, we'll support Windows 10 before it releases

.