The email subscriptions feature will involve new processes that regularly check for posts scheduled to be sent out via email, so with that in place, we'll be able to support federation on scheduled posts, too.
This was mentioned in #writefreely issue #76 (https://writefreely.org/issues/76)
Email subscriptions are huge, huge; one of those features you think is relatively simple to build until you realize it needs to do that.. and also that.. oh and that, too.
Things are looking good enough to ship this in Write.as Labs soon. Last pieces:
- verifying email addresses
- sending posts on a delay