The discussion revolves around disabling per post email for existing users after turning off “mailing list mode” in a Discourse forum. Senthil initially asks if it’s expected behavior for users who registered when “mailing list mode” was ON to still receive emails for everything. To achieve the desired behavior, Senthil proposes editing user settings in the database and setting category tracking level defaults historically.
fefrei cautions that actively changing settings for all users might go against their manually configured intentions. Instead, fefrei suggests only changing defaults, not touching existing users, and educating them on how to configure their email settings. If changes to user settings are made, fefrei advises reducing the amount of mail users get, such as disabling mailing list mode only for users who still have it on, and then informing users of the changes and how to revert if desired.
Yes, this is something you’ll do in the Rails console, and the topics you linked to provide good guidance.
However, before you go on, please consider that you’re actively changing settings for all users, possibly against their (manually configured) intentions. A less intrusive alternative would be to only change the defaults (as you did already, at least for mailing list mode), not touch existing users, and write a post that explains to them how they can configure the amount of mail they get themselves.
If you decide to go ahead with changing user settings, I’d recommend that you make sure that you only reduce the amount of mails that users get. For example, disabling mailing list mode but setting a category to Watching for all users is not safe in this regard: What if the user already disabled mailing list mode intentionally? Instead, I’d recommend that you filter for the list of users that still have mailing list mode on, and only for them disable mailing list mode and watch a category instead. After that, I’d write a post explaining what settings you changed, what that means for your users and how they can revert if they liked the old way.