@drohm @hippietywhoop how Mastodon used to do "Messages" was not really direct messages, but instead just a regular post that @ mentioned the recipient and set the post to be visible only by the recipient.
That's why the feature itself is no longer called Private Messages or Direct Messages and instead called Private Mentions, which is what it is. A proper DM feature doesn't exist on Mastodon as of yet, it's just that some frontends and clients have UI that show these private mentions as DMs.