I’ve been using the Golden Master version of iOS 4 for a few days now, and so far it’s been pretty good. There are a few bugs I’ve noticed, so I don’t think this will be the final version. Here are some changes I noticed while using iOS 4:
Apple changed the Music app to show the album art when viewing an album. Not anything major but it’s a change.
The settings app now has airplane mode, brightness, and sounds on the main page (I don’t think sounds or brightness were there before). I’m not sure why an iPod touch needs airplane mode, that could be a bug.
The home screen now has a new dock, wallpapers (I jailbroke mine, the iPod touch 2g doesn’t support it by default), and folders. Also, Apple changed some of the icons.
Not much to show here, I don’t think Game Center is usable yet.
When you double-tap the home button, it brings up a list of running apps instead of the iPod controls like it used to. You can still use the controls by swiping to the left, and you can lock the screen orientation in portrait mode with the icon on the far left. Apparently the music controls will be able to control any backgrounded music app, but there aren’t any apps to take advantage of it yet. Until 4.0 apps start showing up in the App Store, you will only be able to background default apps. To close a backgrounded app, touch and hold the icon for a couple seconds and a close button will appear.
I’m not sure if it’s just my iPod, but the battery life is pretty bad. The night I updated, I went to bed with a 75% battery and woke up to a dead iPod. I’ve read that battery life has improved for some, so I don’t really know.
When I tried to turn my iPod on after the battery had died, it didn’t show the icon that tells you it needs to be charged, it was just a black screen. When I plugged it in, instead of showing the charging icon before it had enough of a charge to boot up, it was just a yellow screen.
Another thing I noticed is that all the default wallpapers are missing. There is an option to choose an Apple wallpaper, but there aren’t any in there. You can choose your own picture from your gallery though.
This obviously isn’t a default feature of the OS, but I just thought I would mention that not very many things work with 4.0 yet. Winterboard crashes Mobile Substrate, and SBSettings doesn’t work. Those are the only things that I’ve tested so far.