What's new?

The latest developments for Add-On developers.

Support for Manifest Version 3

Thunderbird 128 ESR is the first Thunderbird release to officially support Manifest V3. The required changes to convert a Manifest V2 extension to Manifest V3 are listed in our WebExtension API documentation.

Updated sample extensions to Manifest Version 3

We updated our sample extensions to be compatible with MV3. Each extension includes comments to highlight the required changes.