Upgrading MacBook Pro Mid 2012 to Catalina

Catalina only supports 64-bit applications, and this does not pertain to individual documents, including your stated Pages and Numbers documents. You can use your same Apple ID that you used to install Pages v7.1 and Numbers v5.1, after you upgrade to Catalina to get Pages v11.1 and Numbers v11.1 installed, the last compatible versions for Catalina. After the upgrade, you can launch the Mac App Store signed in with same Apple ID and press cmd+0 (zero) to open the Purchased panel. You should see Pages and Numbers there with a blue outline cloud symbol that you click. A sheet should descend and offer to install the last compatible version of these applications for Catalina. Don't click Cancel on any dialog.

If your current printer, scanner, or multi-function device is shown as supported by Apple's built-in AirPrint (when networked), you wont' have to worry about whether the vendor provides device drivers for Catalina.

The iWork '09 suite of applications are 32-bit apps and will not work in Catalina, nor will Office 2011 for Mac, nor any of the Adobe CS6 or earlier applications. It would be wise coming from High Sierra to check which of your existing third-party applications are 32-bit, and the free Go64 application can do that for you. Some vendors may now have 64-bit application updates for their older 32-bit applications, have abandoned the Mac, or like Adobe, expect a subscription.

Greetings GrandmaAUST,

Sometimes when updating the macOS you can get this message because the apps will also be in need of an update. The ability on the older documents being able to open will depend on the changes made to the apps themselves.

If you recently installed a new version of macOS, some apps may need to be updated or reinstalled. See Install and uninstall apps from the internet or disc.

You can see the above information and more here: If you can’t open an app on Mac. If you have further questions, you may want to reach out to Apple directly. You can reach out to them by clicking here: Contact Apple Support or over the phone by calling the number that is most local to your region: Contact Apple for support and service.

Best wishes!