Hello there, @greidig13-gmail-.
The new feature for QuickBooks Desktop mobile app is only available for 2021 versions, and it only applies to the receipt management. If you're using versions lower than QuickBooks 2021, you'll need to update the software for additional features.
However, if you update QuickBooks Desktop Pro, then go back to the mobile app the data doesn't auto-sync since QBDT and QBO are 2 different software.
To learn more about the new feature we rolled out, check out this article: What to expect with QuickBooks Desktop 2021
Also, I've added this handy QBO desktop app user guide that contains info about the different keyboard shortcuts, its system requirements, etc. This way, you can maximize the app's features to your advantage: QBO Desktop app User Guide.
However, if you meant something else, I'd appreciate any extra details you have so I can provide the steps to move forward. Looking forward to your reply. Enjoy the rest of the day.