On Friday, Apple released the much awaiting Apple iPhone 2.1 firmware upgrade, and it has been primarily met with praise as many issues have been addressed including that nasty security issue, application crashing and stability issues.
Apple provided an official changelog, however a MacRumors forum user has an extensive list which include: Podcasts listings indicate partially listened to items; iPod song listings show artist and album name; Improved compatibility with certain bluetooth headsets; Triple clicking on the headset button goes to the previous track; Pause application installations by tapping on the icon.
However, it appears some 3rd-party apps are having compatibility problems with the iPhone 2.1 firmware.
Source — macrumors