Why is Epyrus based on TB 52.6 code when latest "classic" was TB 52.9.1? Topic is solved

[LeeBinder]

Latest TB fully supporting legacy XUL extensions was 52.9.1 (July 10, 2018), with the source code still being publicly provided by Mozilla:

https://archive.mozilla.org/pub/thunder ... .1/source/

Why did you choose the 5½ months older 52.6.0 (January 25, 2018) as codebase for Epyrus?

I searched the forum for an answer, to no avail, but would like to understand

[andyprough]

You might be able to get some insights into why 52.6 was selected by looking through the reelase notes from the first Seamonkey release of 2.49.2 in February 2018 after Thunderbird 52.6 was released in January 2018. From the ghacks article about the February 2018 Seamonkey release:

It is highly recommended that you back up the profile folder before you run the update as some files may not be compatible anymore with older versions after the upgrade. ... Mozilla changed the internal format of the browsing history database.

and

SeaMonkey users who use the built-in email client may run into issues as well. Summary files may not be read properly if you downgrade SeaMonkey after having upgraded it to the latest version. SeaMonkey users should delete the .msffiles in the local folders and for Pop3 accounts to avoid data loss and resolve the issue.

and

The team notes that some extensions may not work properly anymore in SeaMonkey 2.49.2. The browser is based on Firefox 52.6 ESR currently. SeaMonkey does not support WebExtensions currently because of that. This is going to change but likely not anymore in 2018. The Mozilla backend code SeaMonkey is based on, now usually incorporates breaking changes in every release. This is especially true for the Mozilla Gecko add-ons code and the JavaScript interpreter. Consequently, some older extensions may no longer function properly.

[from https://www.ghacks.net/2018/02/16/seamo ... -2-is-out/]

[LeeBinder]

Hi @andyprough thanks for your reply, and it seems it was good to raise this topic because after studying your reply and following the link you provided, here's what I can contribute from my research knowledge:

1. Thunderbird has left Firefox'es ESR scheme in Nov. 2013 with v.17.0.11esr, see https://en.wikipedia.org/wiki/History_o ... hunderbird. Ever there after, there has never again been a TB v.<XY.ab.c>esr line which would still receive security updates analog to Firefox. As per https://wiki.mozilla.org/Thunderbird:Home#Releases, "Thunderbird Project version numbers for releases match to Mozilla Firefox ESR numbers". But that's all - it's just a merely cosmetic matching of numbers, with no ESR functionality behind it. If v.52.6.0 had been ESR, there would've been v.52.6.1/2/3, but there never have been. The next version was 52.7.0.

Summed up, TB v.52.9.1 is a much "ESR" as is v.52.6.0.

2. Accdg. to my information, Seamonkey has always been and still is mainly a browser with some email functionality added to it. It is not a fully-featured email client like Thunderbird and Epyrus. Altered JavaScript interpretation beyond v.52.6 has never been as huge as an issue for Thunderbird extensions as it has been for Firefox extensions.

3. I didn't have to leave one single TB extension behind from v.52.6 > v.52.9.1. From what I remember there was only 1 which needed a little tweak to revive it for v.52.9.1, that was all (as we'll all agree, the big loss began with TB 53.0)

Even though in retrospect with years having gone by since end of 2018, it might still be useful to inspect changes from TB v.52.6 > v.52.9.1, and at least evaluate which improvements to implement into the current code base (I guess it would not be feasible to start fresh with the latest TB XUL v.52.9.1 codebase and apply all the Epyrus code to it)