I've been holding off updating all my purchased apps until the 2.1 upgrade so I could test for this bug with the latest firmware. I updated 8 apps today and didn't lose any user data. I've previously lost user data updating various apps with versions 2.0 and 2.0.2, using the same update method. Obviously, one update session with the 2.1 firmware is not conclusive. Has anyone here lost user data while updating apps on a device with 2.1?