We recently switched from version 4.1.0 to version 4.3.7. The reason was that we have to support IE11, as we still have to support IE9, we chose not to update to the latest version.
The page https://developer.jboss.org/wiki/PrioritizedRichFacesBrowsersCompatibilityMatrix made us think the 4.3.X branch was still maintained. As it turned out, it is not. So, how can one find out what branches are maintained?