Can I update beyond 9.3.5 on iPad 3

No (other than as Niel suggested iOS 9.3.6 for a cellular iPad), your iPad is too old, too under powered and completely incapable of running the now required 64 bit software for the newer iOS versions.

If you need the newer iOS levels, you need a newer iPad.

If your unit doesn't have a GPS, no. If it does, you can update to 9.3.6, but this will only fix a date rollover issue with it.

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