Apple has released the beta version of its next iPhone software update to developers. iOS 4.3 is thus being combed through by news sites and blogs to see what new features are upcoming. 9 to 5 Mac has found something interesting: a reference to a feature called Media Stream and Photo Streaming, with the latter seemingly allowing iPhone users to create streams of photos that friends can subscribe to. Media Stream is much more mysterious, but the article speculates that it could involve (legal) music sharing, with links to the iTunes Store. Separately, it’s emerged that in iOS 4.3, Apple’s Ping social music service will be able to send push notifications.