Aside from the touted application switching interface and the iPhone 4's FaceTime video telephony, almost all of the applications and services currently found in the iPhone/iPd platform will be given new features. A walkthrough at the TiBb blog covers all aspects of the Version 4 update, what was previously called the iPhone OS.
Here are a few items that caught my eye:
Bluetooth Keyboard Support You’re going to get tired of us saying “like the iPad” but remember when we told you spring’s influx of iPad news would be important come summer’s new iPhone news? You were warned for a reason. iPhone is getting iPad’s Bluetooth keyboard support. Thank goodness for that.
Of course, the iOS 4 features depend on the capabilities of the hardware model in question. The Bluetooth keyboard support will only work on iPhone 3GS and iPod touch G3 (2009) and above.
There are also changes for the Calendar. According to the article, Apple will open the Calendar to third-party developers.
What this means is you may soon see apps where you can buy tickets for a local movie and have the show time automatically added to your Calendar.
One feature that is now available to enterprise-configured iPhones is a strong passcode. For the rest of us, the current passcode lock is a short 4-digit PIN. With iOS 4, all users will gain the more-secure feature.
That means you’re no longer stuck with only a 4 digit pin, but can now create longer passcodes with far greater variation. Of course, longer, more varied passcodes are more of a hassle to remember and enter, but that’s the cost of good security
All the talk of iOS 4's multitasking is somewhat overstated — the iPhone and iPad aren't gaining the full background multitasking found in Mac OS X. As Apple's developer intro site explained a while ago, there are seven multitasking APIs available:
-Background audio - Allows your app to play audio continuously. So customers can listen to your app while they surf the web, play games, and more. -Voice over IP - Your VoIP apps can now be even better. Users can now receive VoIP calls and have conversations while using another app. Your users can even receive calls when their phones are locked in their pocket. -Background location - Navigation apps can now continue to guide users who are listening to their iPods, or using other apps. iOS 4 also provides a new and battery efficient way to monitor location when users move between cell towers. This is a great way for your social networking apps to keep track of users and their friends' locations. -Push notifications - Receive alerts from your remote servers even when your app isn't running. -Local notifications - Your app can now alert users of scheduled events and alarms in the background, no servers required. -Task finishing - If your app is in mid-task when your customer leaves it, the app can now keep running to finish the task. -Fast app switching - All developers should take advantage of this. This will allow users to leave your app and come right back to where they were when they left - no more having to reload the app.
Of course, what customers will notice first is the fast application switching interface. Not only will users be able to switch between applications but they will be able to experience persistence, the saving of application states. Now, when applications close down, they really close down. If you need to get back to where you were were, then you have to make some form of bookmark. This behavior may be alright for book-style content, but not for a game.
A few developers tried to add persistence on their own, saving your place when you came back as best as previous OS versions allowed, but most didn’t — especially games which was aggravating when phone calls pulled you unexpectedly out of them. Also, if you closed one app and went to another, you could theoretically be stuck swiping back or forth between 11 home screen pages.
Saved state is now built into iOS 4. If you switch out, Apps have their currents state saved to memory and if/when you go back, the app checks the memory save and resumes from that state.