~ 2012 Apple iPad Retina Display 10.1”.
Apple iPad Retina Display was the lighter faster upgrade to the original iPad 1. The biggest and most undesirable update to me was Apple’s addition additional features to an otherwise simple Zoom magnifier accessibility setting, Adding features and options made set-up and saving desirable screen magnification levels far more complicated than the original iPad. One major flaw included the fact that the magnification option listed on the screen do not magnify until one manipulates the unit. Thus, if you are visually impaired you might not be able to read the Zoom magnification options while trying to set your preferred view.
Noting in later versions of iPads an unchanged or similar Zoom magnifier software I have been reluctant to a newer iPad. The lack of a built-in stylus is a smaller, but significant additional reason I have yet to upgrade the iPad Retina Display.