On Thursday Google update its offline HTML5 Gmail app with a couple new features for when you're unable get a connection. In addition to the usual performance tweaks, shortcut junkies will be pleased to find keyboard shortcut support that mirrors your settings on regular Gmail. Perhaps the biggest improvement, now under Settings, is the option to save up to a month's worth of email locally — or just one or two weeks. If you've got the app installed, these updates should appear the next time you load the app; otherwise, grab it from the Chrome Web Store.