Which of my apps won’t work after system upgrade?

You’ll need to check each App individually within the App Store. There’s no shortcut to checking which Apps will work - and those that won’t.

Each App in the App Store will show if the App is compatible with your iPad - and the minimum system requirements for the currently available version of that App.

Whether or not you are able to update any iPad to a newer version of iOS/iPadOS will be dictated by the iPad model - and the currently installed version of iOS. You can find this information here:

Settings > General > About

Not sure which iPad you have? Identify your iPad model.

Here is a list of the highest version of iOS supported by the older models of iPad (for simplicity - “generations” are shortened to a number) that are restricted in their ability to be updated:

iPad1 - iOS 5.1.1

iPad2, iPad3 and iPad mini1 - iOS 9.3.5 (WiFi Only models), iOS 9.3.6 (WiFi & Cellular)

iPad4 - iOS 10.3.3 (WiFi Only), iOS 10.3.4 (WiFi & Cellular)

iPad Air1, iPad mini2 and iPad mini3 - iOS 12.5.5

Newer models, not appearing in this list, are all able to be updated to the current version, iPadOS 15.5

Unless the App is iPad hardware specific (which is generally only applicable to high-end models of iPad - by example, the current iPad Pro models with a LiDAR sensor), the actual model of iPad is largely irrelevant.

Older Apps, that have not been updated to use updated/modified system libraries may not work after update of the iPad to a later major version. This is not a fault of iOS/iPadOS, but is simply the App Developer failing to keep their Apps updated; Apps that no longer receive update support, having been abandoned by the respective Developer, will eventually be removed from the App Store.

Forward compatibility is not necessarily guaranteed. As with any Operating System, if there are installed Apps upon which you are critically dependent, the onus is on the user to verify with the Developer that the App/Application continues to be compatible with the updated OS.

You may find that an App Developer has their own website where you may find additional information - or you should seek more information directly:

How to contact an app developer - Apple Support

As an example, for an iPad Pro 12.9” M1, for the Google Chrome App as viewed in the App Store:

As you can see, the App is shown to be compatible with this iPad.

Tapping the entry to expose the system requirements, we see this - showing that the App requires iOS/iPadOS 14.0 or later: