Not sure what you mean about developers keeping old versions. So far as I know iOS will only install from the App Store. Do you have an example of a developer doing that?
The latest version (16.04.05) of Acrobat Reader requires iOS 8.0 or later.
However, the App Store can provide the latest compatible version of Adobe Reader for your iPad or iPhone running iOS 7 (or even older version of iOS).
- Go to the App Store app on your iPad/iPhone.
- Find Acrobat Reader.
- Try downloading the latest version of Acrobat Reader.
Please tap the Download button to install the previous version of Adobe Reader.
If you see the dialog with the OK button only (i.e. no Download button), it means that you have never installed Adobe Acrobat Reader using the particular Apple ID before.
To associate Adobe Acrobat Reader with your Apple ID, you will need a Windows or Mac computer and iTunes (desktop app).
- On your iPad/iPhone, check the Apple ID that you use for the App Store (Settings > iTunes & App Store).
- On your Windows or Mac computer, open iTunes.
- Sign in iTunes using the same Apple ID that you use on your iPad/iPhone.
- Find Acrobat Reader and download it to your computer. (Do not try to install it on your iPad/iPhone because the latest version is not compatible with your iPad/iPhone anyway.)
Now you can switch back to your iPad/iPhone and try downloading the latest version of Reader. You will be presented with the dialog with the Download button.
You can add annotations and fill out PDF forms using the older version of Reader.
Please let us knows if it works for you.