Unread PM cancel option

[escrow.ms]

Is that possible?

Mybb allows that.

Tracking
    This option allows you to track messages you have sent - allowing you to see if and when a user has read your message. If they have not read the message, you can delete the message from their inbox.

[🏰 TradeFortress 🏰]

This can be done using images that track hits.

[escrow.ms]

This can be done using images that track hits.

No not just tracking,I was talking about pm cancel option.

I quoted that tracking text from mybb's site.

[🏰 TradeFortress 🏰]

That wouldn't work as people can get email notifications of PMs. Deleting something from their inbox won't remove the message that was already sent via email.