Use iOS custom keyboard for Sales Emails Extension
The current iOS client workflow for tracking e-mails is quite broken.
On one hand, it doesn't work for replies/forwarded e-mails, and also, to track a new e-mail I need to go and create it first in your app, then "sign" it and then email it.
I would suggest that you take advantage of the custom Keyboards in iOS to have a "single button" custom keyboard that allows me to "track" an e-mail that will insert the needed pixel to the body of the e-mail.
This way I can use it in my normal mailing workflow on iOS without the need to switch to your app for a simple e-mail or reply to an e-mail.
I never checked, but it could be that just by being a custom keyboard, you can detect when the e-mail is opened by the owner and prevent the ghost/wrong notifications when I open my own e-mails.