Likely timing of future Thunderbird Gecko builds
R Kent James
kent at caspia.com
Tue Apr 18 05:22:27 UTC 2017
TL;DR: Our branch of Gecko-esr59 may be the last version of
mozilla-central that we support for Thunderbird.
In my post from September 17, 2015 "Future Planning: Thunderbird as a
Web App" I proposed a likely future schedule. I said:
"Thunderbird 59: Last and traditional XUL/C++ release. By this date, a
reasonable possibility is that the Mozilla platform will no longer be
usable for non-browser XUL-based development. This version of
Thunderbird, in that case, would need to ship on a fork of Mozilla from
the point where XUL-based development becomes untenable. This will also
be our last major XUL-based release, and we will not attempt to keep
current with the new non-XUL Mozilla platform."
Though 19 months have passed since that post, I still stand by that
timing, and I think we need to seriously start planning our likely
relationship to Gecko releases. Mozilla is talking about major changes
beginning with Gecko 57, so we will probably need to branch Gecko at
that point. We'll try to keep the branch as close to Gecko-esr59 as
possible, so that while Gecko-esr59 is active we will be able to merge
security changes. After EOL of Gecko-esr59 in late 2018, we will be on
our own, responsible for continuing security updates to our mozilla branch.
That means that after Thunderbird 59, we will cease trying to maintain
Thunderbird builds based on Gecko 60 and later, but will instead
continue all further development of existing Thunderbird (which should
be regressions and security patches only) using Gecko-esr59. After EOL
of Gecko-esr59, that will require increasing effort to maintain security
patches, such that this path is probably only viable for at most a year
after EOL of Gecko-esr59.
That also means that during the mozilla-maintained lifetime of
Gecko-esr59, we will need to devote all available effort and resources
in a race against time to have a viable Thunderbird++ before the costs
and risks of maintaining our fork of Gecko-esr59 becomes untenable.
What might change this? If the mozilla breakages at Gecko 57 are less
than we fear, it might be possible to to continuing maintaining a
Thunderbird build on Gecko for 60+. But we should make a hard decision
at that point, and not just assume that we will continue the substantial
effort to keep Thunderbird buildable on mozilla-central.
Per https://wiki.mozilla.org/RapidRelease/Calendar current schedule for
merge of Firefox 60 to central is 2018-01-15, so we will need to decide
before the end of the year whether to cease attempting to build
Thunderbird on future Gecko versions.
More information about the tb-planning