December 2023 – A user will be able to opt in via the Threads app to have their posts visible to Mastodon clients. People would be able to reply and like those posts using their Mastodon clients, but those replies and likes would not be visible within the Threads application. Threads users would not be able to follow or see posts published across Mastodon servers, or reply to them or like then.
Early 2024 (Part One) – the Like counts on the Threads app would combine likes from Mastodon and Threads users
Early 2024 (Part Two) – replies posted on Mastodon servers would be visible in the Threads application
Late 2024 – A “mixed” Fediverse and Threads experience where you will be able to follow Mastodon users within Threads, and reply to them and like them
TBD – Full blended interoperability between Threads and Mastodon
http://plasticbag.org/archives/2024/01/how-threads-will-integrate-with-the-fediverse/