Also a big deal:
"For a long time, the plugin has spoken the server-to-server half of ActivityPub fluently, which is how your posts reach Mastodon, Pixelfed, and the rest. With 8.1.0, the plugin now also exposes an ActivityPub API, an implementation of the Client-to-Server (C2S) half of the protocol. In plain language: third-party Fediverse apps can now create, edit, and delete posts on your blog directly, the same way they would on a Mastodon account."