Up until now, Firefox, Thunderbird, and SeaMonkey users, used a single portal for extensions for their products. Even users of Firefox-based browsers could point their browsers to https://addons.mozilla.org/ to search for, download, and install browser extensions.

Today's launch of https://addons.thunderbird.net/ changes that.Thunderbird and SeaMonkey users cannot use Mozilla's Add-ons website anymore to download extensions for the email client or web browser as they need to use the new website instead. Redirects are in place to make the migration as smooth as possible for users.

One core factor for the decision to fork the Thunderbird and SeaMonkey extension repositories was that Mozilla plans to remove legacy extensions from its platform in the near future (meaning 2018 likely).

Considering that Thunderbird and SeaMonkey do support legacy add-ons still, and will for the foreseeable future, it was clear that something needed to be done about it to provide users with options to download compatible extensions.

Img

Another factor that played a role was that Thunderbird development and management was split from Mozilla even though the project remained under the umbrella of Mozilla Foundation. With Thunderbird and SeaMonkey becoming independent products, more independent than they have been before, it was clear that the projects wanted full control over the add-ons platform.

The new platform is a fork of the old Thunderbird and SeaMonkey listing on Mozilla's Add-ons website. In fact, when you try to open any Thunderbird-related link on Mozilla's site you will notice that you are redirected automatically to the new site.

Everything works identical to how it was before; even user reviews, ratings, old extension versions and such have been carried over. The functionality is identical at this point in time and users who used the old platform before will feel at home right away. You can even sign in with a Firefox account just like before and developers can do the same to manage their extensions for the platforms.

Thunderbird and SeaMonkey users who have installed extensions in clients at this point in time don't need to change anything. Mozilla redirects update URLs automatically so that new updates will get picked up just like they have previously.

The two main entry points for Thunderbird and SeaMonkey extensions are:


The new add-ons site is managed by the Thunderbird Council and it runs on Mozilla infrastructure. Mozilla helped the Thunderbird Council with the forking and making sure that everything worked after migration.

Closing Words

The migration to an independent platform ensures that Thunderbird and SeaMonkey extensions remain available online. While it would also have been possible to leave the directories untouched on the Mozilla Add-ons website, doing so was not really an option because it would not give the Thunderbird Council full control over the platform and because of the removal of legacy features on Mozilla's Add-ons website which might have impacted functionality.