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While the Mozilla Foundation’s Firefox Web browser garners most of the headlines, the open-source group’s Thunderbird e-mail client is also attracting users’ attention. Mozilla Thursday released the latest beta edition of the program.

Although Thunderbird’s 1.0 launch date is around the corner, developers are continuing to add new features. The two biggest additions in the new 0.9 version are Saved Search folders (aka Virtual Folders) and Message Grouping.

A Saved Search folder looks like any other ordinary mail folder, but when you click on it, the folder first runs a search according to your previously set search conditions and then presents you with the results. For example, you could set a Saved Search folder to show you only messages from your boss from the last 30 days.

Besides working with mail on your PC, you can also use Saved Search with mail resident on IMAP servers and Usenet newsgroups.

With Message Grouping, you can organize messages in the open folder into self-contained groups according to their date, sender, subject or any other criteria by which you choose to sort your messages. For example, if you set your Inbox to group messages by date, the messages will be organized into folder-like groups labeled Today, Yesterday, Last Week, and so on. Or, if you group by subject, your folder would be sorted into a listing of subjects.

You cannot, in this beta edition, use Message Grouping and Saved Search folders together. They will work together in future versions of the program, according to Mozilla.

Click here for eWEEK Labs’ take on Thunderbird 0.8.

Thunderbird also boasts numerous bug fixes and other minor improvements, including improved privacy controls that now automatically block remote content in e-mail messages from senders not in a user’s address book. This will help defend users from Web-based e-mail attacks.

According to some reports, the latest Thunderbird version is an easy upgrade from earlier versions. However, there have also been reports of the application freezing on XP when upgrading from 0.8 to 0.9.

The latest version of Thunderbird will also not run extension programs and themes that worked with version 0.8 or earlier versions. Many of these extensions are now being updated to be compatible with version 0.9 and can be downloaded at The Extensions Mirror.

Like earlier versions, Thunderbird 0.9 runs on Linux, Windows and Mac OS X.

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