Why am I no longer able to see when one of my customers has VIEWED their invoice? It used to show every single time they VIEWED the invoice but it does not any longer

Hello there, dougntina.

I'm here to help you view the invoice status. 

Recently, we updated the way to review the invoice standing. Here's how:

1. From the Sales tab, select Invoices.
2. Locate and click the invoice.
3. On the prompt page, go to the Invoice activity section.

Another way to review the status is through your customer's profile. Below are the steps to achieve this goal.

1. On the Customers page, select the customer name.
2. Go to the Transaction List page.
3. Click the invoice transaction.
4. Go to Invoice activity.

Furthermore, I've added this article on how to record invoice payments: Record invoice payments in QuickBooks Online.

I'm always around whenever you have concerns about tracking invoices.