Note that since JSF is integrated into
JEE servers, unless the WAR overrides it, the JSF version in use is determined by the
server, not the web application.
Unfortunately, I don't really know a good way to check the JSF version required to properly run a webapp. In theory, the schema version of the faces-config.xml file would do it, but it's not a reliable indicator.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.