"mailing list mode" mysteriously deactivated

[osioke (Osioke Itseuwa)]

I see how not knowing ahead of time is upsetting, we try our best to carry the community along and the change was mentioned here

@jomaxro

Mailing List Mode default disabled

Mailing list mode can generate significant email volume, especially on sites with a large user base. This can be unexpected for site owners who don’t realize users can turn on mailing list mode themselves. We now disable mailing list mode via site settings by default so sites don’t experience an unexpectedly large cost from outgoing email. Site owners that wish to allow mailing list mode on their site will need to uncheck disable mailing list mode in site setting.

Tracking release-notes and #feature:announcements would keep you notified of these changes.