While iOS 4.2 final is not yet released to general public, developers has already got access to iOS 4.2.1 GM for iPhone, iPod Touch and iPad. You can download iOS 4.2.1 GM from the iOS Developer Center if you’re a registered Apple developer.
iOS 4.2.1 GM is aimed at fixing major Exchange and audio issues.
If you’re enrolled in the iPhone Developers Center, you can download iOS 4.2.1 GM from the link below:
We will keep you updated as soon as iOS 4.2/4.2.1 final hits masses. Stay Tuned!