Avast IS Update Error

Avast IS cannot update engine or virus definitons. I’m running Windows 7 SP1.
Current version 2015.10.2.2214 but 2015.10.2.2215 is available.
On attempting to update, the following message returned: unknown error; already up to date.
Anyone any ideas?

Try avast repair

Controlpanel > Ad / remove programs > avast > uninstall / change > repair option

Did that change anything?

Or perform a clean installation of the latest version (advised)
https://forum.avast.com/index.php?topic=169255.msg1203279#msg1203279

2215 is also outdated, follow the instructions in the earlier posts for a repair and if that fails a clean install with latter 2218 https://forum.avast.com/index.php?topic=169887.0

Apprecite the helpful responses.

Repair threw an error but clean install woked a treat :).

Issue resolved. Thanks!