Today Apple allowed developers to get their hands on the third beta of iPhone OS 4.0. The latest major revision to the OS carries over 100 new features and seven major features.

When Apple announced iPhone OS 4.0 the company demonstrated these seven major features:

  • Multitasking
  • App Folders
  • Enhanced Mail app
  • iBooks for iPhone and iPod touch
  • Enhanced enterprise features
  • Game Center
  • iAd

Apple also alluded to the following features:

  • File & delete Mail search results
  • Search SMS/MMS messages
  • Web search suggestions
  • Choose image size in Mail messages
  • Bluetooth keyboards
  • CalDav invitations
  • Larger fonts for Mail, SMS & alerts
  • Cell data only setting
  • Spell check
  • Persistent Wi-Fi
  • Gift Apps
  • Birthday calendar
  • Recent Web searches
  • Create Playlists
  • Sync IMAP notes
  • Top Hit in search
  • 5x digital zoom
  • Nested Playlists
  • CardDav
  • Tap to focus video
  • Upload workouts to Nike+
  • Places in Photos
  • iPod Out
  • Home screen wallpaper
  • Search SMS/MMS messages
  • Wake on wireless

Let’s take a look at what’s present in the third beta of iPhone OS 4.0 (captions below images). Changes at first look appear to be slim but the third beta does represent a far more stable release.

As illustrated in the first image (below) Apple has now included a “portrait orientation lock” accessible by double-clicking the home button and swiping the app tray left. The lock forces the iPhone to stay in portrait mode, the iPhone cannot be locked into landscape.

iPhone OS 4.0
Left: Home screen with custom wallpaper, note orientation lock icon in task bar. Middle: App folders now have iPad-esque backgrounds. Right: The App tray has a new background and now multiple apps can be quit at once.

iPhone OS 4.0
Left: Swiping left on the App tray now reveals the orientation lock button and iPod controls. Middle: iPod controls and orientation lock. Right: Even when iPhone is in landscape orientation the App dock appears on the right of the display.

iPhone OS 4.0
Left: About. Middle: Although began working in beta 2, this is a screenshot of Places. Right: Individual icons are pinned on the map in Places.