Now it's out for the iPhone as well, and we know an iPad update is coming soon. Given how quickly the iPhone update followed Android's, I would bet Facebook probably had both versions ready at the same time, but had to wait for Apple's much more stringent app approval process.
The second change in this version is expected: three months ago, Facebook launched Subscriptions, so it's about time the iPhone app lets users access them. As for the last bullet point, performance improvements are never detailed, but are always welcome.
Either way, for Timeline Mobile, Android got the feature before the iPhone. When the Facebook Platform for Mobile was released, the opposite happened: iOS was first and Android was second.
Facebook for iOS remains the most popular app in the iTunes App Store. Version 4.1 is compatible with the iPhone, iPod touch, and iPad, but requires iOS 4.0 or later, according to Facebook. It officially supports 13 languages: English, Chinese, Dutch, French, German, Italian, Japanese, Korean, Polish, Portuguese, Russian, Spanish, and Turkish.