3.1.3 for Windows brings Sn0wbreeze jailbreak for iPhone 2G, 3G and iPhone 3GS (older bootroms only) which can preserve your older baseband while upgrading you to the latest iPhone OS 3.1.3 firmware. This means that you can now unlock your iPhone 3G and iPhone 3GS using the current version of ultrasn0w (for 04.26.08 baseband) or blacksn0w (for baseband 05.11.07) as they both are compatible to work with the respective baseband older versions.