Can't find anything that indicates this in docs.
ExpressionEngine® Answers is a question and answer site for administrators, end users, developers and designers for ExpressionEngine® CMS. It only takes a minute to sign up.Sign up to join this community
Wygwams requirements are on the Docs Installation page it just says EE 2.7 or better.
Wygwam 3.X is definatly compatible with EE 2.9.3 and 2.8.1, there have not been any changes to the plugin functionality within EE since 2.8.1 AFAIK.
I note that the Wygwam changelog that patches have been added to support down stream technologies (EE < 2.5, PHP < 5.3), their support is done through this site (expect BrandonKelly to chime in soon!!) and I can't find any reports of incompatability.
All indicators point to good support.