Sprint and HTC have released the Android 2.1 update for the HTC Hero. Like the update that recently went out for the HTC DROID Eris for Verizon, this Hero firmware update must be downloaded and applied from a personal computer.
Sprint notes that applying this update will delete your personal data. The following is the official warning:
Important Note: Installing the 2.27.651.5 update will delete all the data and information on your phone. You will lose contacts that have not been synced to an email account, text messages that have not been forwarded, saved voicemail messages older than 5 days, voicemails older than 20 days that have not been listened to, and call history. The calendar and email settings will also revert back to factory defaults. Pictures, music, videos and files are stored on your microSD memory card, which should be removed before updating your phone.