Do you have an iPhone 3GS that is still running iOS 6.1.6? Do you want to download Facebook on your device and stay connected with your friends and family? If yes, then you might be wondering how to do it since the latest version of Facebook requires iOS 10 or later. In this article, we will show you how to download Facebook on iPhone 3GS with iOS 6.1.6 using iTunes and iFunBox. Follow these simple steps and enjoy Facebook on your iPhone 3GS with iOS 6.1.6.