Mind elaborating a bit on what you mean? Like mark as read on posts/stories? I could add it in.
Hopefully it’s OK to mention competitor iOS clients - but Octal does grey out read items.
What would be even more useful is a mode where if I decide not to read certain posts (based on their titles) by scrolling past them, I'd like to have them automatically marked as "seen" so I won't have to read their titles again.