My iPad won’t let me download a certain app until iOS 13 I been waiting on a update for months

Many older models of iPad cannot be updated - as their internal hardware cannot support newer versions of iOS/iPadOS. As such your iPad may be one of those that are incapable of supporting iPadOS13 or later - such as iPad1-4, iPad mini1-3, or the iPad Air1.

Many App developers have dropped support for iOS versions preceding iOS 13.x for technical reasons, often because APIs or software libraries upon which they rely have been updated in the new version of iPadOS, making their App incompatible with earlier versions.

Whilst many App titles remain compatible with older models of iPad, if you have one of the older models and want or need to access to Apps requiring the most recent versions of iOS, you’ll need to consider replacement of your iPad with a newer or current model that supports iPadOS16. The current entry-level iPad9 supports iPadOS16 and will run all currently available Apps.

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:

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 models are all able to be updated 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)

If your iPad is capable of update to a more recent version of iOS/iPadOS than is currently installed, these support pages outline both the available methods by which the update can be performed - and troubleshooting should you experience difficulties:

Update your iPhone, iPad or iPod touch – Apple Support

If you can't update or restore your iPhone, iPad or iPod touch – Apple Support

If your iPhone, iPad or iPod touch won’t update - Apple Support

iOS update and restore errors – Apple Support

Be aware that while an iPad may be capable of update, in some circumstances you may need to use a computer to perform the update. To do so, you will need access to either a Window PC (with iTunes for Windows installed) or a Mac (with iTunes or Finder - as appropriate for the installed version of MacOS). Ensure that your installed version of iTunes has been updated to the most recent version; the essential device drivers are included.

Download and use iTunes for Windows – Apple Support

Update to the latest version of iTunes – Apple Support

Update software on iPhone, iPad or iPod touch in iTunes on PC - Apple Support

If you have a beta profile installed, ensure this has been removed from your iPad - as, otherwise, installation of production software updates may be inhibited. This support page provides the necessary information to remove the beta from your iPad:

How to uninstall iOS beta software - Apple Support

You should note that for your iPad to install an available update, its battery must be charged to at least 50% capacity - and/or be connected to its Power Adapter. Similarly, the iPad can only be updated over a standard WiFi connection - or be updated by a PC or Mac using iTunes or Finder - over a USB connection.

iPadOS 13 has been superseded a long time ago. The latest version of iPadOS is 16.3.1.

You didn’t say which iPad model you have. If it’s an original iPad Air, or iPad mini 2 or 3, they can only be updated to iOS 12.5.7.

Identify your iPad model – Apple Support (UK)

Hi Malikmctoy11,

We'll be happy to look into this with you. If you're referring to an application that requires iOS 13 to operate, and your device is on a lower iOS version, you would need to update (assuming your device is compatible with iOS 13).

The following article shows how to update: Update your iPhone or iPad

"Update your iPhone or iPad wirelessly

1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.
5. 
6. 
   
7. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.

"

Cheers.

I suspect that you are waiting in vain. iOS13 has been superseded a long time ago. You don’t say what iPhone model you have but if it is a 6 or earlier it cannot be updated beyond iOS12 (current precise version is 12.5.7). This would explain why you’re not getting an update. If you have a newer phone follow the advice given by jmarse1.

This answer made by AKRBTN is not relevant because it is about iPhone not iPad.

Yes fair point. I forgot what forum I was in!