Firefox 57 is probably the most important release of the browser for Mozilla ever since the browser was released in its initial version.
The browser comes with the first bits of Quantum, a new technology that improve rendering and other areas, the deprecation of the legacy add-on system and the overboard throwing of legacy components, theme improvements, and more.
We talked about how this affects users of the Firefox web browser, but not so much about other programs and products that share code with Firefox.
These programs have two main options when it comes to their future: adopt the same changes and accept the new direction that Firefox takes, or support the legacy features that Mozilla won't support anymore.
The first option is the easier one from a technical point of view, but it means that users of these programs may face the same issues that Firefox users will face when the browser hits version 57: old add-ons won't work anymore is the biggest of those.
The second option ensures compatibility with legacy technologies and add-ons, but it is more complex from a technical point of view. The main issue with this approach is that these projects cannot use most of the Firefox code anymore that Mozilla puts out after the release of Firefox 57 (at least not without modifying it). The implementation of new web technologies and other improvements may take longer because of that.
Pale Moon shares most of its code with the Firefox web browser. It supports Firefox add-ons and themes, NPAPI plugins, and many other features that made Firefox what it is today.
Pale Moon won't follow Mozilla when it comes to the changes made to the browser. This means that Pale Moon will continue to support features such as legacy add-ons or NPAPI plugins, and that it won't support WebExtensions, Quantum, or other new technologies.
Work on Pale Moon continues, version 27.6. was released the other day, and work will continue in the coming months and years.
The team behind Pale Moon is working on a hard fork of Mozilla's code platform that includes features that Mozilla dropped for the Firefox 57 release. This browser will be the fundament of a new XUL-based browser platform that the team could migrate the old Pale Moon browser to.
Could be, because a final decision has not been made yet in that regard.
Waterfox filled a gap when it came out; it offered a 64-bit version of a Firefox compatible browser at a time when Mozilla did not really provide one for the Windows operating system.
Waterfox's developer, Alex Kontos, has plans for the browser that look similar on first glance to what the Pale Moon team has planned for the future of the browser.
The browser is moved to an ESR's code base based on Firefox 56 to buy more time. The developer plans to support legacy Firefox features such as XUL or XPCOM in Waterfox, and even wants to create a unique add-ons website that users of Waterfox may go to for all add-on needs.
The most recent update of Waterfox moved the browser's profile to its own location. Waterfox used Firefox's profile by default previously, but this is no longer possible without risking issues, as Mozilla made modifications already to data stored in the user profile.
There is a lot of uncertainty in SeaMonkey's future. The de-facto successor of the Mozilla Application Suite includes a browser and also other applications such as an integated email client, IRC chat and RSS feed client.
The team released information about the application's future back in May 2017. It had plans to move to Firefox ESR as the code base to support legacy features for longer. While that is the case, support for legacy features will be dropped eventually in SeaMonkey.
Updates have not been posted to the best of my knowledge.
Thunderbird has had some rocky years as well. Mozilla wanted to separate the email client from its core product Firefox, and the team behind the email client had to find a new home as well as infrastructure because of that.
Development will continue as an ESR version for the time being.
I think it is surprising that some projects are still undecided in regards to future development. Firefox 57 will launch next week, and Firefox ESR will also be only available with legacy support until mid 2018.
Now You: What's your take on the future of these products?