How to upload existing add-on to new site?

[sigh; score -1 for the new 2FA login scheme - I had to create a new Discourse account as my old one used my Firefox email but setting up 2FA won’t let me access that. Grr.]

OK, so one of my extensions used to be for both Firefox and Thunderbird. As such, it’s not been migrated.

However, I had to rewrite it using WebExtensions for latest Firefox releases, so current versions don’t support Thunderbird.

I now need to post a patch release to set the compatible-with-Thunderbird 60 flag, so … what do I do?

Do I upload it as a “new” add-on to the new site? Will users automatically see it?