What is the Difference Between Apple iOS 4.2 (iOS 4.2.1) and Apple iOS 4.3?

Apple iOS 4.2 (iOS 4.2.1) and Apple iOS 4.3 are two versions of Apple's operating system. iOS 4.3 was released with iPad 2 in early March 2011 and introduced new features and improvements compared to iOS 4.2.1. Some of the key differences between Apple iOS 4.2 (iOS 4.2.1) and Apple iOS 4.3 include:

1. iTunes Home Sharing: This feature was added in iOS 4.3, allowing users to share their iTunes libraries across multiple devices.
2. Improved Video Streaming and AirPlay Support: iOS 4.3 introduced enhanced video streaming and support for AirPlay, including additional support for photo slideshows and third-party video and audio editing applications.
3. Safari Performance: In iOS 4.3, Safari's performance was improved with the new Nitro JavaScript engine.
4. Personal Hotspot Functionality: iOS 4.3 introduced the ability to function as a personal hotspot, while iOS 4.2 did not support this feature.
5. Device Compatibility: iOS 4.2 supports the iPhone 3G and second-generation iPod Touch, while iOS 4.3 does not.

In summary, iOS 4.3 brought several improvements and new features compared to iOS 4.2.1, including better Safari performance, iTunes Home Sharing, enhanced video streaming, and personal hotspot functionality. However, it no longer supported the iPhone 3G and second-generation iPod Touch.

Comparative Table: Apple iOS 4.2 (iOS 4.2.1) vs Apple iOS 4.3

Here is a table comparing the differences between Apple iOS 4.2.1 and Apple iOS 4.3:

Please note that there were several updates released between iOS 4.2.1 and iOS 4.3.2, including 4.2.5, 4.2.6, 4.2.7, 4.2.8, 4.2.9, 4.2.10, 4.3, 4.3.1, and finally 4.3.2. The differences between iOS 4.3 and iOS 4.2.1 may not be due to the most recent patch alone but are cumulative across all updates.