The Thunderbird e-mail client still has its supporters, but for the past couple of years, Mozilla has been making moves to distance itself from the project. In late 2015, Mozilla announced that it would be looking for a new home for Thunderbird, calling its continued maintenance "a tax" on Firefox development.

Yesterday, Mozilla Senior Add-ons Technical Editor Philipp Kewisch announced Mozilla's future plans for Thunderbird—the Mozilla Foundation will "continue as Thunderbird’s legal, fiscal, and cultural home," but on the condition that the Thunderbird Council maintains a good working relationship with Mozilla leadership and that Thunderbird works to reduce its "operational and technical" reliance on Mozilla.

As a first step toward operational independence, the Thunderbird Council has been soliciting donations from users, which Kewisch says has become "a strong revenue stream" that is helping to pay for servers and staff.

"Our infrastructure is moving to thunderbird.net and we’re already running some Thunderbird-only services, like the ISPDB (used for auto configuring users’ e-mail accounts), on our own," he writes.

In the long-term, the Thunderbird Council would also like to end its reliance on Mozilla's Gecko rendering engine, but for the foreseeable future, the e-mail client will continue to use Gecko and to stay close to Mozilla "in the hope that it gives us better access to people who can help us plan for and sort through Gecko-driven incompatibilities."

If either the Mozilla Foundation or the Thunderbird Council becomes unhappy with the new arrangement, either can "discontinue the Mozilla Foundation’s role as the legal and fiscal host of the Thunderbird project" with six months' notice. For now, though, this looks like an acceptable compromise for both sides: Thunderbird won't be unceremoniously dumped by Mozilla onto some other organization without the resources necessary to develop and maintain it, and Mozilla won't be saddled with sole responsibility for paying for and developing Thunderbird.