Updates
My iPad is out of date and can no longer be updated what should I do?
iPad, iOS 10
As you correctly observe, your iPad4 cannot be updated.
Update support for iPad4 ended September 2017. The final iOS releases for this model were iOS 10.3.3 (WiFi Only models) and iOS 10.3.4 (WiFi & Cellular). iPad4 cannot be updated to any later major version of iOS as it lacks the minimum hardware requirements needed to run more recent versions. The 32-bit platform upon which the iPad4 is built is obsolete.
Many App Developers have dropped support for 32-bit devices and iOS versions preceding iOS11/12/13 - and have withdrawn older versions of their Apps from the Apple App Store. Withdrawal of Apps supporting older models of iPad is making their utility and usefulness significantly more limited.
Also be aware that an unsupported iPad does not benefit from security updates. For some applications, such as financial and banking, from a security and privacy perspective are unsafe to use.
If Apps that you need to use now have higher minimum iOS-version requirements than your iPad can support, your only real option is to consider replacing your iPad with newer model. If you are concerned for your security, replacement of an obsolete device is advisable.
Of current models, even the entry-level iPad8 supports current iPadOS 14 - and has hardware specifications and capabilities that vastly outperform your old iPad4.
I hope this information is helpful - if only in clearly stating the limitations of your iPad4 and your available options.
