I think many of you still remember Eudora, once a popular free email client. Mozilla has took over the project and renamed it to Penelope. The good news is Mozilla has released a beta version of this email client for all of us to try it out. Many of you may be wondering why Mozilla is developing Penelope as they already have a popular Thunderbird on hand. Well this is what quoted from Mozilla site :

Eudora is a mail and news application from Qualcomm based on the open source Thunderbird client from Mozilla. It’s *not* our intention to compete with
Thunderbird; rather, we want to complement it.

Qualcomm is committed to both preserving the Eudora user experience and to maintaining maximum compatibility, for both developers and users, with
Thunderbird. It is our goal to build a single development community around Thunderbird and Eudora, so that both mailers advance faster than they
previously have.

Whereas “Eudora” is a branded version of Thunderbird with some extra features added by the Eudora developers, “Penelope” is an extension (also
called an “add-on”) that is used in Eudora and can also be used with Thunderbird. The Eudora installer includes the corresponding version of
Penelope along with it so there is no need to install Penelope if you are installing Eudora. Most features in Penelope can be accessed when used with
Thunderbird, but there are a few that require Eudora in order to work correctly and it’s not something that gets tested.

Sometimes in documentation there is a need to differentiate the older versions of Eudora made by Qualcomm from current Thunderbird-based versions
of Eudora. This will normally be done by labeling the older versions of Eudora as “original Eudora” or “Classic Eudora”.

You can download the beta version at Mozilla website