Why WhatsApp is suddenly unable to open any APK shared by users?

As of 13-11-18, I was sharing APK files on WhatsApp, for testing apps within a circle of people, with no problem whatsoever. But as of today, if I try to open an apk, I get an error toast saying: > You may not have the proper app to view this content. Did they change their policies and decided not to let people share APK files on their platform? I don't use third party websites for sharing APKs, where mostly Chrome spooks most people saying that "This type of file may harm your device".