@amberage @jo Yeah, one of the few things AT protocol gets right vs ActivityPub is the notion of allowing the user to control their data silo and post history.
Currently the only post migration option I know of for ActivityPub is slurp for GoToSocial, which requires server access and is intended for self-hosted micro-instances, really.
https://docs.gotosocial.org/en/latest/user_guide/importing_posts/
https://github.com/VyrCossont/slurp?tab=readme-ov-file#importing-a-mastodon-archive