Board Thread:Questions and Answers/@comment-38858299-20190319055439/@comment-33165688-20190319141544

The Don, Leo and Raph issues all take place shortly before the current arc of the series, because they all focus on events (Don's encounter with Metalhead, Leo's deal with Karai, Raph's capture) that are tied directly to the current arc's events or character development.

The Mikey one takes place shortly after Kingdom of Rats, since that involves the bringing of the children to the Foot Clan.