All updated mastodon instances use activitypub for federation between themselves and only use ostatus when federating to gnusocial instances. I'm not sure of the version where this switch happened, but instances not updated to that version would still use ostatus solely.
If I understand correctly activitypub is implemented by MediaGoblin....

My understanding is that:

    OStatus is a decentralized social networking protocol made up of several other protocols (Atom feeds, Activity Streams, PubSubHubbub, Salmon, and WebFinger)
        GNU Social and Mastodon are two server software applications that implement OStatus API is an interface to the server software (Activity Streams, OAuth, Web Host Metadata) is a instance (not accessible right now), GNU MediaGoblin is a server application that currently uses a pump-like API
    ActivityPub is a proposed decentralized social networking protocol
        GNU MediaGoblin is a server application that will likely implement ActivityPub

How do these protocols interoperate? Does ActivityPub completely replace OStatus, or only the Activity Streams component?
AFIAK Mediagoblin did have a GSOC 2017 goal for ActivityPub but it doesn't look like it was worked on as the Savanna git's federation branch was last committed to 22 months ago.

I've been hoping for some interaction with ActivityPub, but at least since they use PostgreSQL at the very least the database itself can store JSON in the same format ActivityPub sends
It's just a matter of someone coding it.
 my house near the sea,  
With great sadness I discovered today that our friend Tony B. aka Tazman has left us.
My great adventure companion and friend in these 6/7 years of free foss networks.
Rest in peace my friend and find serenity in the other dimension <3 ... <3

Pink Floyd - " Breathe "
by HDPinkFloyd on YouTube

#libertree #redmatrix #hubzilla #friendica #gnusocial #diaspora