No, we are not self-hosted.
Discourse provides our hosting and also provides some degree of technical support. I don’t know the exact nature of our agreement, but they keep our software up to date and respond to bug reports and issues. They don’t do admin stuff like manage our site settings and such though.
Since Discourse manages the software for us, we generally aren’t involved in installing updates and don’t really know ahead of time when they are coming. We can check in the admin control panel to see when they’ve last installed an update, so they don’t hide it from us or anything, but they manage it all for us. We can also check to see what has changed in the updates.
So I would expect that sometime in July or so they’ll roll out that update for us and we’ll lose support for those old browsers.