I cannot access invoices since the forced update and have now not been able to bill clients. Using FreshBooks and exploring other software.

This isn't the kind of experience I want you to encounter with our newest version of the QuickBooks Online (QBO) mobile app, sikes.

I can only imagine how challenging that situation must have been for you when accessing the invoices in the app.

There are several causes why these issues occur on your end, and I've listed them below.

• The Operating System (OS) version isn't compatible with the program.
• The mobile app stores too much cached data. 
• There's a problem during the update or installation.

Not to worry, I've got the steps to resolve the problem. Allow me to provide them below.

First, make sure your phone's OS is supported. If you're using an iPhone or iPad,  use the 9.3 or later. For Android Phone & Tablet, have 4.1 or later.

Then, let's clear the app's cache. It retains data, which can cause an unusual response to the system. I'll show you how:

Android: 

1. From your device's Settings, select Apps (varies by device).
2. Choose the QuickBooks app from the list.
3. Select Storage. 
4. Tap clear data.

iOS:

1. From your device's Settings, select Setting General iPhone Storage.
2. Choose an app that's taking up a lot of space. 
3. To free up the storage without deleting the documents and data for the app, select Offload App.

If the issue persists, I recommend uninstalling the software. Then, reinstall it to refresh the system. 

In the meantime, you may consider logging into your web browser. There, you can view your invoices.

Finally, I've added this resource to help you learn more about which features are supported on each device: Compare mobile app features.

I appreciate you for posting here in the Community. I'm committed to providing you with the best possible experience. If you have any further questions or concerns, please don't hesitate to get back on this thread. I'm dedicated to resolving any issues you may have.