Updating an old iPad

Presumably your iPad indicates that it must be restored:

If you see the Restore screen on your iPhone, iPad, or iPod touch - Apple Support

These support pages outline the available methods to restore an iPad - either from a backup, or to Factory Settings:

Restore your iPhone, iPad or iPod touch from a backup – Apple Support

Restore your iPhone, iPad or iPod to factory settings – Apple Support

Restore all content to iPad from a backup - Apple Support

You’ll need access to either a Windows PC (with iTunes for Windows installed - or more recent Apple Devices App) or a Mac computer (with iTunes or Finder - as appropriate for the installed version of macOS).

Download and use iTunes for Windows – Apple Support

Update to the latest version of iTunes – Apple Support

Apple Devices App (Windows PC):

https://apps.microsoft.com/detail/9np83lwlpz9k?hl=en-ms&gl=MS

Use of a PC or Mac computer is unavoidable. If you don’t have access to a suitable computer of your own, that of a helpful friend or family member will suffice. Alternatively, the technicians at the Genius Bar of your local Apple Store or Apple Authorised Service Provider (AASP) will be delighted to assist.

Genius Bar Reservation and Apple Support Options - Apple

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 15.8.2

iPad5, iPad Pro (9.7"/12.9" first generation) - iPadOS 16.7.8

(*) obsolete

Newer models are all able to be updated to the current version - iPadOS 17.5.1

• iPad Pro 13" (M4)
• iPad Pro 12.9" (2nd generation and later)
• iPad Pro 11" (1st generation and later + M4)
• iPad Pro 10.5"
• iPad Air (3rd generation and later + M2)
• iPad (6th generation and later)
• iPad mini (5th generation and later)

You're very welcome. I'm delighted that you managed to successfully resolve your difficulty.