iOS 4.3 Changes
For iPhone 3GS & 4 (GSM only), iPod touch (3rd generation & Above), iPad and iPad 2
* Initial release on iPad 2 is March 11
* Bug Fixes
* AirPlay video support for third party apps
* HTTP Live Streaming Statistics
* New font in Notes app ("Noteworthy")
* A slightly “redesigned” keyboard with a different graphic under each key in the App Store
* Improved Safari Performance with "Nitro" JavaScript Engine
* Redesigned “account” section under the Store menu
* Location services has been shifted from General to Settings Menu
* New Parental Controls for use with Ping
* Location services & Mail accounts ON/OFF button changed to a lock symbol
* New menu for scrubbing in videos
* Fine Scrubbing: Adjust by seconds/ frames
* Quarter Scrubbing: Second
* Half Speed Scrubbing: Adjust by minute(s)
* Hi-Speed Scrubbing: Run fast through minutes
* Ability to cancel and delete an app which is currently downloading. Before iOS 4.3 it was only possible to delete an app which has already downloaded.
* Stream from an iTunes library to iOS using Home Sharing.
* In-app purchases always ask for a password, even if one has previously been entered
iPhone only
* Personal Hotspot feature (Wi-Fi Hotspot with up to 5 simultaneous devices (Wi-Fi Hotspot iPhone 4 Only)) on supported carriers.
* Ability to set amount of times a text tone repeats (up to 10 times)
* In Field Test Mode refresh button has been removed & Updated information has been displayed in bottom of the screen (it updates every 4–6 seconds)
* Slideshow options moved to Photos app
* New look for taking a picture for a Contact
* When receiving a text message, the iPhone now vibrates 2 times
Bug Fixes (From official Apple Changelog)[69]
* Accessibility
* Fixed issue that prevented controls from being dismissed in some cases
* Addressed issue where the keyboard could not be brought back when highlighting and swiping through search results
* Voice over now reads the entire chart in stocks app while in landscape mode
* AirPlay
* Fixed slideshow stop after 15 image when using AirPlay
* Baseband & Telephony
* iPhone -> 05.16.00 (for 3Gs), 04.10.01 (for 4)
* Updated carrier settings (U.S. is AT&T 10.0)
* Enabled Traffic Volume Indicator IE in CELL UPDATE
* Fixed issue with integrity protection failing after SRNS relocation
* Fixed issue of iPhone units deactivating and not activating after baseband logging is enabled
* iPad -> 07.11.00
* Fixed issue of Physical channel reconfiguration failure during a reselection procedure
* Fixed issue of the UE missing a page because it is decoding and responding to RRC Setup messages meant for other UEs
* Fixed incorrect auto routing with LG HBM-210 on FaceTime calls
* CalDAV
* Fixed canceled recurring calendar events still shows on the event list
* Calendar
* Fixed deleting a recurring events make the alarm go away
* Fixed all-day alarm fired an hour early
* Exchange
* Fixed exchange calendar event duplicating when passing Israeli daylight savings time
* Fonts
* Letter ł is now visible in notes (zYx- letter ł IS visible in notes in 4.2.1, WAS visible in 4.1, 4.0.1 and 4.0! [1])
* Keyboard
* Fixed missing accented letters in European keyboard popups
* Increase font size for China and Pinyin inputs
* Fixed auto-correction issue when switch back from Emoji to English keyboard
* Added inline space with Pinyin inputs
* Corrected “Undo” translation in Simplified Chinese to “撤销”
* Localization
* Updated inconsistent translation in Chinese, Finnish, Norwegian, Korean, Dutch, Polish, Portuguese
* Fixed missing Chinese characters in Pinyin
* Improved common phrases used in Chinese
* Improved common phrases used in Japanese
* 劲歌金曲 is no longer missing
* Fixed issue that produced unexpected output when trying to type 从前门进入果
* 一点儿 now ranked higher than 一点二
* Word completion candidates capability now available for Chinese language
* Added additional common phrases for character 耍
* Fixed issue that caused the wrong candidates to be displayed (J: “間スコット”) when “ますこっと” is input
* “軽さ(かるさ)” now in the candidate
* Mail
* Fixed orientation of mail application not following device orientation under specific conditions
* Fixed popover when drilling into a thread while the empty search field is focused
* Fixed mail message view and orientation when quickly selecting a message and hitting edit mode
* Messaging
* Fixed MMS messages with vCards scrolling up
* Phone
* Fixed screen not drawing properly when Nike+ is in the background
* Security
* Added [Address Space Layout Randomization] (ASLR) [2]
* Status bar
* Added new icon for Wi-Fi Tethering for personal hotspot on status bar
* Web
* Fixed issue that caused Safari and other apps to crash after loading certain heavy Websites
* Fixed Personal Hotspot password failure with 22+ characters
* Jailbreaking Ability
* Fixed Untethered Exploit By Chronic-Dev Team.
* VoiceOver
* Added support for “find” in Safari
* Fixed wallpaper titles for VoiceOver
http://en.wikipedia.org/wiki/IOS_version_history