Mozilla has released Thunderbird 3.1, an update to the company's free desktop e-mail software. The previous release Thunderbird 3.0, was a less than stellar application, but thankfully, the latest version fixes the bugs and sees the Thunderbird project back on track. In fact, Thunderbird 3.1 is what 3.0 should have been. Unfortunately, Thunderbird 3.0 was marred by some serious bugs that failed to import user's mail from older versions of Thunderbird. It also had a habit of becoming unresponsive while indexing large mail stores. The new version of Thunderbird does not, thankfully, suffer from the same problems. To test the new importing feature, we dug an old Thunderbird 2 POP mail store off a backup disk and imported it into the latest version without losing any mail. Thunderbird 3.1 is also remarkably faster than its predecessors -- particularly when indexing messages in large mailboxes. While Thunderbird 3.0 had a number of nice new features -- a tabbed interface, improved search and overall UI -- the features were largely useless thanks to endless hangs and spinning cursors. Particularly notorious for those connecting to Gmail was the "All Mail" folder which generally caused Thunderbird to hang, sometimes for hours. With Thunderbird 3.1, we were able to grab all the headers for some 17,000 messages in just over ten minutes. Even better, the rest of the program was perfectly responsive and usable even as the messages were downloaded and indexed. Thunderbird's search tool is also considerably faster in this release. The search tool, which first arrived in 3.0, rivals Gmail's search capabilities and offers additional filters that make it easy to narrow your search by sender, date and more. Thanks to the improved indexing speed, the search tool is also much quicker in this release. Thunderbird 3.1 isn't just about correcting Thunderbird 3.0's bugs and speed issues, there are several new features as well. The new Quick Filter makes it easy to filter messages by Unread, Starred, Contact, Tags or Attachments. There's also a handy button to make filters persistant even when you're changing folders. The only thing missing in the new Quick Filter tool is a way to customize filters. While you can't add your own filters to the new Quick Filter bar, there is an extension that adds a few more features, like the ability to filter based on sender and date. Also new in the latest version of Thunderbird is a "saved files" manager for dealing with attachments. Similar in appearance and function to Firefox's Download Manager, the Saved Files Manager displays all the files you've downloaded from your e-mail to your computer, making it easy to find them later. Thunderbird 3.1 also has a new Account Setup Wizard. While it looks the same on the surface, hundreds of ISP settings have been added, which means Thunderbird is much better at guessing your settings. Just enter your name, e-mail address and password and Thunderbird will configure the rest of your setup for you. While on the whole Thunderbird 3.1 is a much needed improvement over its predecessor, it's worth noting that the new app has a new set of system requirements, including the need for a worrying 1GB of RAM. Considering that the 2.0 release only required 64MB, it's not hard to see why some call the the Thunderbird 3.x line "bloated." In our testing Thunderbird never went over 250MBs of RAM, but that's still a significant jump from 2.0, which was considerably less RAM-heavy. Thunderbird 3.1 is also not without its annoying quirks. For example, search results are limited to 10 results, forcing endless clicks of the "more" button to see all the results. Similarly, while the ability to select multiple messages and see a snippet of each is one of the handiest features in Thunderbird, the snippets are only two lines, often not quite enough to get the gist of a message. Other niggling complaints include burying the option to turn off HTML e-mail three menus deep in the account preferences section. And of course Thunderbird's platform integration -- that is, how well the UI fits the various OSes it runs on -- lags well behind its sibling, Firefox. More serious complaints include the inability to sync contacts with popular webmail providers like Gmail and Yahoo. There is an add-on that will work with Gmail, though it hasn't yet been updated to support Thunderbird 3.1, but frankly, contact syncing should be built into the app. Still, even if you have to manually import your contacts, Thunderbird 3.1 is a worthy e-mail client and definitely worth the upgrade if you're using 3.0. If the horror stories of early 3.0 adopters put you off and you're still using Thunderbird 2, it's safe to jump back in the water. Even if you swear by webmail interfaces, Thunderbird is a good option to keep around for backing up your accounts. Just periodically fire up Thunderbird, let it download your messages and you'll spare yourself the pain when Google shuts down your e-mail account for no apparent reason. Thunderbird 3.1 is a free download, you can grab a copy from the Mozilla Thunderbird website.