Opened and Seen mean a recipient's mail app loaded a tiny image that Newton adds to emails you send with read receipts. Usually that means they opened your email, but not always.
How it works
In your email list, a double tick appears next to an email you sent with read receipts. It's gray until someone opens the email, then it changes color. On desktop, point at it to see Opened or No opens yet.
In the conversation, click or tap the tick next to your message to see who opened it and when: the Read Status tab on desktop, or the Read receipts tab on your phone. It reads Not yet seen, Seen once or Seen 3 times, and lists anyone who hasn't opened it as Not opened.
Opens by the same person less than 10 minutes apart count as one.
A reply from a recipient counts as opened, even if their mail app never loaded the image.
Newton ignores opens by bots and security scanners. It also ignores opens from the same internet connection as your own Newton devices, so a colleague on your office network may show as Not opened.
Good to know
Some mail apps, such as Apple Mail with Mail Privacy Protection, load images automatically. An email can show as Seen before anyone has read it.
If a recipient's mail app blocks images, Newton can't see the open, so the email stays Not opened even after they read it.
With Outlook accounts, Newton can't tell which recipient opened the email. When you send to several people, only the first recipient is listed, and an open by anyone shows there.
The list tick describes only the newest message in a conversation. Once someone replies, the tick leaves that row.