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This is the eighth beta. This contains various bug fixes, localization tweaks (including a new Italian localization), and one UI change in particular: .Mac is now MobileMe. Search is fixed, as are some issues with MetaWeblog servers. There is a fix for a crash when synchronizing Palm devices. There are some various other fixes as well that are detailed in the Version History. There aren't any new features as 5.1 is feature complete already. Providing more localizations is also a goal for this release. Please let me know if you have any problems with this beta.