Intent to de-support: traditional add-ons

Graeme musiquegraeme at
Tue Oct 8 13:22:29 UTC 2019

I managed to make my addon work with MailExtension Experiments which was largely using the 
bootstrapped version and turning the bits I needed into experiment APIs.

But this email and others I have read tell me that I'm going to have to eventually move 
into a MailExtensions addon and I really don't know that there is anything that I've seen 
that goes beyond a Hello World example. I looked at a number of pages mentioned on these 
emails and found all the broken or non existant links. I found the list of APIs that looks 
impressive but I don't think is any longer in the area of composition than it was months 
ago. I'm sure they are very helpful for those who understand them but, for me, they may as 
well be in Chinese.

What I'd really like is a number of working addons that I can look at and get ideas from.

I looked at the Addons that are available and was *very* surprised to see how many of the 
*featured *addons are still legacy. They require restart. I wish there was a place or a 
list of the working MailExtension Addons.

I realise that all the people who know what they are doing are *very* busy maintaining 
legacy addons and keeping up with Firefox changes etc. I hope that once legacy addons are 
dropped there will be more time for documentation that can help those of us that have 
survived as MailExtension Experiments.


On 05/10/2019 16:26, Onno Ekker wrote:
> Op 5-10-2019 om 13:53 schreef Magnus Melin:
>> On 05-10-2019 13:37, Onno Ekker wrote:
>>> Can I have a little more clarification on this?
>>> As an add-on author, I always tried to keep my add-ons working during
>>> the daily/beta release cycle.
>>> I think you are telling us add-on developers now too, that it doesn't
>>> make much sense in trying to keep our XUL Legacy add-on or
>>> bootstrapped add-on compatible with Thunderbird 71.0a1 or later,
>>> because it won't work in Thunderbird 72.0a1 or 73.0a1 anyway, let
>>> alone in Thunderbird 78.
>>> Is that also what you implied?
>> Yes that is correct. Support for non-WebExtension add-on will be
>> dropped, so "keeping up" won't help, unless you convert it to a
>> supported format.
>>   -Magnus
> And do you think SeaMonkey will follow suit(e)?
> I mean, they share your infrastructure, so they can't keep using
> And maybe there will ever be a SeaMonkey 2.57 or SeaMonkey 2.65, which
> will hopefully support the same add-ons as Thunderbird 60 and 68 does.
> But they can also stay on 2.49 and keep backporting security patches,
> but then they must probably do the same for a future
> or something like that...
> Onno
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