Future of Thunderbird after 1.5 release

With the release of Thunderbird 1.5, the spotlight is now on how the application development will move on from here. 3 versions are planned, with the release plan for Thunderbird being similar to that of Firefox.

A graphical roadmap has been created by Asa Dotzler.

1.5.0.x (for code off the MOZILLA_1_8_0_BRANCH) will be released from the Gecko 1.8 branch, but will only contain stability and security updates. 1.5 users will want to update to this if bugs prevalent in 1.5 are fixed in these new versions.

2.x (for code off the MOZILLA_1_8_1_BRANCH) will also be released from the Gecko 1.8 branch, involve “UI improvements and other ideas which don’t require changes to existing APIs“, and tentatively be out in summer 2006 (or later).

3.x should be out by mid or late-2007 and will be based on Gecko 1.9. The new Gecko 1.9 foundation will provide a basis for major architectural changes in the backend codes and APIs.

Do note that whatever checkins are made in the MOZILLA_1_8_1_BRANCH will immediately be checked in to the trunk, otherwise, as Brendan Eich goes, “We’ll end up with a big-bang landing as happened with the Aviary 1.0 branch. Also, we are more likely to end up with a bugfix or change to the branch pulling all of Gecko over from the trunk, as happened during Aviary 1.0. And mainly, we must keep enough community QA on the trunk so that it does not regress badly”.

By immediately checking in, all “post-Aviary” mega branch-to-trunk merger problems can be avoided, including “requiring developers to merge and land changes in two places (trunk and a major branch)”, as conflicts, errors and even negligence (of no one’s fault) to check in to both locations (instead of only branch or only trunk) may result. More information, including an FAQ, is available here.