Thunderbird Will Phase Out Legacy Add-Ons, Will Support WebExtensions (bleepingcomputer.com)

Catalin Cimpanu, writing for BleepingComputer: Mozilla announced last week plans to modernize Thunderbird's codebase, plans that include fixing some "technical debt" by incorporating the recent changes in the Mozilla engine into Thunderbird, adding a new user interface (UI), and phasing out old legacy add-ons that are built on the XUL and XPCOM APIs. The changes are part of Mozilla's new plan for Thunderbird development, a project that it left for dead in 2012, but later decided to reinvigorate in 2016.

Comments

Now for some credit where I feel it due...

[thegreatbob]

... to a possibly surprising recipient: Despite being a crusty/unreliable piece of crap, Outlook has no shortage of features, and exposes them in not-particularly-difficult-to-find ways. The UI is probably the least 'afflicted' by the ribbon of the various Office products I've used in recent history, as the ribbon winds up getting used more like a conventional menu. While we are not expecting Thunderbird to be a full-featured Outlook knock-off, the current set of features (while missing a few) is still quite good; any reduction thereof means they're taking a step back, and no longer see themselves as a viable competitor to the old behemoth (regardless of if it is true or not.

Closing statements, directed towards The Mozilla Foundation:

I will continue to use Thunderbird, even older versions, until it becomes a security liability and/or no longer does what I need it to do.
I will have little choice but to return to Outlook for work purposes, if WebExtensions is to be ramrodded down our collective gullets.
Thunderbird may very well be your last opportunity to prove to the world that you have not completely lost your way; don't blow it.

Re: What do you use instead for lots of email?

[loufoque]

I moved everything to GMail.
Not ideal, but it can deal with the data, and has other advantages to.