WhatsApp is the most popular instant messaging platform which is available for both Android and iOS smartphones and also for desktop and laptops. Over the years, several new features have been added to this instant messaging app, but it still has a green theme. You can change the wallpaper; however, the theme can't be changed. There are some modified versions of this app which you can download and run on your Android smartphones and do skin customizations as well. FMWhatsApp app is one of those applications which give you all the security features besides the new themes.