If there's no mention of an update, it means there wasn't need to mention it, since the scenery hasn't really changed, but we changed the installer version, likely because something that was changed in the installer itself so, if an user has a problem that might be related to the *installer*, we could know which installer he used by asking the version number.
In this case, the difference between KLAX 1.3.1 and 1.4, it's the installer that has the Live update of the AFCAD file for KLAX, so it always downloads the latest version of the AFCAD which has been optimized for GSX (but of course it works even without it)
