The problem being I don’t know exactly know when it came in - but I do suspect avast 2016, but there were 3 program updates for 2016 12.1.x 12.2.x and 12.3.x. So it may be possible to try one of the earlier ones or possibly avast 2015 or even avast 10.x.x.

The problem then is finding a source for old versions some I have suggested in the past offer old versions, but many use an on-line installation (meant for the old version) but it automatically downloads the latest version.