If you have tried updating to the recently released iOS 4.2.1 update on iPhone 4 and encountered Error Code 1013 or Error Code 1611, then you are a not alone. This has been a common issue across all iOS devices updating to iOS 4.2.1 and Apple Support Discussion forums are full of users complaining about this issue.
Apple has just released the very final version of iOS 4.2.1 for iPhone 4, iPhone 3GS, iPhone 3G, iPad and iPod touches. This version of iOS brings a number of new features for iPhone, iPad and iPod touch users including: Multitasking, Folders and Game Center for iPad, AirPrint, AirPlay, and other system wide changes and improvements.
