I successfully completed tests to ensure that PayPal IPNs were being properly processed by my app. I did a simulator test, a sandboxed account test and a live account test... all were successful.
Next, I submitted a verification request for my app to Google. All G Suite developers know how tricky this process is these days but thank God mine was completed without any complications or delay.
Finally, I made a few subtle changes to my website to let current and future users know that change is coming to Flookup.