After a couple years, I've been asked by a client to have all of their users subscribed for email notices on new questions asked in their site's Community Answers area.

Is there an easy way to do this? I've found the "Auto Subscribe Users" setting in the Integrations options of Community Answers, but the tool tip makes me think this would only be for new signups, not existing users. I also found a topic to remove all user subscriptions but not how to add them. https://www.corejoomla.com/forum/support/community-answers/16470-users-automatically-subscribed-in-all-categories-by-error.html

I need to renew the license for updates but have to get authorization from said client before proceeding. Please advise if this is feasible and I will get them to authorize it. Thanks!