I'll share additional information about this, montana_numbers.
Once a company file is open to a newer version of QuickBooks, you can no longer open it in any earlier version. You might offer them to acquire a one-time license equivalent to your version, as Fiat Lux - ASIA stated. Otherwise, you can install a QuickBooks Desktop the same to their version if they still have a backup copy of their 2020 file.
To learn more about the company file to avoid issues and errors in the future, check out the following articles below for more insights:
If they wish to upgrade their QuickBooks Desktop 2020, you can share this resource with them for complete details: Upgrade QuickBooks Desktop Pro Plus, Premier Plus, or Enterprise.
You're always welcome to post again if you have further questions about restoring the company file. We're here to help you.
