Eudora OSE is the Open Source Edition of one of the internet's most pioneering and enduring applications. It is a re-imagining and re-implementation of classic Eudora features on top of the Mozilla Thunderbird codebase. It is more than just an extension, as certain functionality required changes to the core of the application. Some of these have been accepted into and become part of Thunderbird, while others are still awaiting acceptance. Eudora OSE integrates so tightly with specific versions of the underlying code that it is highly recommended for users to install the entire application, rather than trying to run the extension on top of Thunderbird.

1. Classic Style, Modern Platforms
Eudora OSE offers users the classic look and feel of the toolbars and menus they're used to, plus more powerful interface customization than ever before.

2. Eudora Power Importer
Eudora OSE's full-featured migration assistant imports your existing Eudora mail, address books, personalities and accounts, filters and converts them to the new internal format.

3. "Who" Done It ?
Eu- knows Who! Eudora's Who column automatically displays the sender's name for messages in inbound mailboxes, and the addressee in outbound mailboxes, creating a streamlined and uncluttered mailbox.

4. Mailbox Navigation and Filtering
Eudora OSE's Group Selection and Type-to-Select features allow every user to be a power user.

5. New Message Selection
When new mail is received, the classic Eudora FUMLUB feature automatically selects the first unread message in the last unread block of messages. Or you can adjust the setting to select the last message in the mailbox.

6. Indexed Searching
Eudora OSE's ultra-fast indexed search functionality can search specific mailboxes, mailbox trees, or every mailbox you have to find the terms you're looking for.

7. Reference Lookup
Eudora OSE adds the power of a reference library to your email experience. Whether you're reading a message or composing one, Eudora's Reference Lookup feature allows you to select a word or phrase and look it up on a variety of online resources.

8. Content Display Controls
Eudora OSE can automatically display remote images in all of your messages, or it can give you fine grain control in the form of whitelists and case-by-case approval.

9. Toolbar Customization
Eudora has long been known for the refinement of its user experience and nowhere is this more obvious than in its classic toolbar configuration system where all available buttons and controls are neatly ordered by menu category.

10. Comprehensive Session Restore
When Eudora closes, all of its open windows - from application settings to messages - are saved and reopened the next time the program is launched for a persistent user experience bringing you right back to the point where you left off.

11. Feature Summary
A feature-set can be challenging to describe in short option labels, so to keep you from having to jump back and forth between the online documentation and the preference configuration, Eudora OSE provides handy tooltips to explain each preference.

12. Advanced Attachment Handling
Eudora OSE's new mailbox format stores attachments directly within the message, but they can be easily extracted to the hard drive with a simple double-click action. The attachments stay linked to their messages, but the mailbox files remain slim and trim.

13. Message Redirection
Incoming messages can be sent to a new recipient "by way of" you, maintaining the original sender's address in the From field. This is particularly useful if you need to pass along a message that should have gone to someone else.

The license of this software is Freeware, you can free download and free use this email client software.