In a rare moment of clarity for a company known for secrecy, Apple has detailed the changes and security fixes that come with the iPhone's 2.1 software update, released Friday.

Apple CEO Steve Jobs promised during an iPod event Tuesday that the new iPhone firmware will fix some of the device's most egregious issues, including call drops and truncated battery life. In addition, security watchers note the update patches 8 security vulnerabilities, including a code execution risk for mobile Safari and the previously disclosed passcode flaw.

The 2.1 software will also improve the accuracy of the 3G signal display. Users should notice performance enhancements as well, from better responsiveness in the text messaging application and contacts to a significantly shorter time to backup the device when syncing with iTunes.

Reliability was also addressed, improving e-mail connection and resolving crashes. POP and Exchange e-mail syncing is more reliable, while those with "lots" of third-party applications should see the phone become more stable.

In the same vein, the installation of those third party apps should also take less time than previously experienced, Apple said.

Three prominent new features come with the 2.1 firmware. Most notably, the Genius song recommendation functionality introduced with iTunes 8 is now accessible from the iPhone, allowing for the automatic creation of playlists of songs that are similar to one another. Another feature repeats text message alerts up to two times after a text message is received if a user does not check it the first time the alert sounds.

The third new feature in 2.1 is designed for that those worried about the disclosure of data after losing their phone. Users can enable a wiping feature, which causes the iPhone to wipe itself clean by deleting all information after an incorrect passcode is entered ten times.