According to MacRumors, Toktumi the company behind the well-known VoIP application Line2 for iPhone, iPod touch and iPad has sent an email to its users warning them from upgrading to iOS 4.2 due to a new bug founded in this version which results in the ringer continuing to ring even after a call is answered when Line2 is running in the background.

Very Good News : For some instant download version is available at GM (Golden Master) of the new firmware 4.2. The download can be started by this page Apple for developers.