A: Hi there! That is great to hear :)

So the upgrade path for you would be to buy 2 additional codes on AppSumo and then Stack them inside your Missinglettr account.

You can follow this link to stack:
https://missinglettr.com/accounts/stack/

If you have any trouble stacking your codes, please get in contact with us via our website/in-app chat and we'd be happy to assist you!