New Search with Advanced Filtering Tools
Search results now include advanced filtering tools. You have the option to filter your results by sender, tag, attachments, people, folder, and mailing list. You can also filter your email using the timeline tool.
New Global Search field and Redesigned Mail Toolbar
The Mail Toolbar is redesigned to include the new Global Search bar. Buttons such as reply, forward, delete, junk are part of each email message. When typing in the Global Search field, Thunderbird autocompletes against your address book. You have the option of searching everywhere or filtering within folders against different parts of the email such as by subject or by sender.
New Mail Account Setup Wizard
The new Mail Account Setup Wizard matches against a database of email settings from popular mail providers so that you will only need to provide your name, email, and password to set up new mail accounts.
The folder pane offers a Smart Folders mode which combines special mailboxes (e.g. Inbox) from multiple accounts together. Smart Folders is now on by default.From an l10n perspective, it would be great if everyone could thoroughly test these new features in their localized release. Like in the two previous beta releases, Thunderbird 3.0 beta 4 is available in 43 languages.