how can i get update an ipad version 4.3.5?

Connect to iTune and Check for Updates (tap to enlarge image)

Update it from iTunes on a computer as described at the bottom of this article; devices running an iOS version prior to 5.0 can't be updated straight from the device. It will be updated to the newest iOS release supported by the device’s hardware, which is iOS 7.1 for devices with at least 512MB of RAM.

The maximum iOS version for the third generation iPod touch and original iPad is 5.1.1.

If you don't know what device you have, append the last three characters of its serial number to http://www.everymac.com/ultimate-mac-lookup/?search_keywords= and load the page.

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