Enter your Substack publication name and The Mirror will find your last post date.
Finding your publication name — it's the part before .substack.com. If your newsletter lives at yourletters.substack.com, enter yourletters. On the web, check the URL in your Substack dashboard. On mobile, tap your avatar → Settings → Edit Profile → scroll to URL.
No newsletter yet, or haven't posted? Close this and set your date manually using the date picker — it works just as well.