Any ideas as to why the app doesn’t update? My customers are opening their invoices, and paying them but quick books is not updating to show this.

Hi there, pbsiteservices-h.

It's possible that data issues in your QBO app is causing the delay in the update when the invoices are paid. I'll share some steps with you on how to resolve common issues when using the app. 

Start by closing and restarting the app. Then, log back in to check if the invoice's status is now updated. 

Second, let's refresh the app's data is you're getting the same result. Follow these steps if you'e using an iOS device:

1. Tap the Burger icon or 3 horizontal lines at the bottom-right.
2. Look for the the Question mark in the upper-right hand corner and tap on it
3. Select Refresh data.

For Android devices:

1. Tap More Options or the three dot ⋮, select Settings, and then tap Refresh Data.
2. Select Yes.

You might also need to uninstall and reinstall the app just in case the issue persists. Let me share this article with you for additional reference: Troubleshooting Quick-Start Guide For The QuickBooks Online App.

Let me know if you need anything else. We're always here to help.