If your iPad is currently running, or cannot be updated beyond iOS 10.3.3/4, then have an iPad4.
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 The 32-bit platform upon which the iPad4 is based is obsolete.
Not sure which iPad you have? Identify your iPad model.
App Developers have dropped all support for 32-bit devices and many for iOS versions preceding iOS11/12/13 - and have withdrawn older versions of their Apps from the Apple App Store.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. Once compatible versions Apps are withdrawn, you’ll not be able (re)download or (re)install them.
Built-in Apps, such as Safari, will also not be capable of accessing some website functionality - as many modern websites will utilise modern browser functions that are unsupported by your iPad. For this reason alone, you are perhaps likely to encounter difficulties.
If Apps or websites that you need to use now have higher minimum iOS-version requirements than your iPad is capable, your only option is to replace your iPad with newer model. Of current models, even the entry-level iPad9 supports current iPadOS 16 - and has hardware specifications and capabilities that vastly outperform an old iPad4.
For information, 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:
32-bit devices (obsolete)
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)
64-bit devices
iPad Air1, iPad mini2 and iPad mini3 - iOS 12.5.7
iPad Air2, iPad mini4 - iPadOS 15.7.3
Newer iPad models are all capable of update to the current version, iPadOS 16.3.1
- iPad Pro (all models)
- iPad Air (3rd generation and later)
- iPad (5th generation and later)
- iPad mini (5th generation and later)
