Apple quietly removed the original iPad mini from its online store today, meaning that all iPads for sale now have a retina display and 64-bit processor.
Michiel Vossen tweeted the change earlier today, which leaves the 16GB iPad mini 2 as the cheapest model at $299. The original iPad mini was introduced in October 2012, starting at $329 for the 16GB Wi-Fi only model. The price was later dropped to $299 in October 2013, before decreasing further to $249 in October 2014.
As all iPads come with a retina display, Apple's lineup now has full support for crisper images and text. The "retina" in Apple's marketing refers to the theory that human eyes cannot distinguish individual pixels on "retina displays" at normal viewing distance. IOS 7, which debuted in 2013, took advantage of retina displays in its design, using ultrathin fonts and minimalistic UI elements. The last iPhone sold without a retina display was the iPhone 3GS, which was removed from Apple stores in 2012.
The 64-bit support across the iPad range also means developers can take advantage of newer hardware when designing apps and games. IOS 9 allows developers to restrict their apps to run only on 64-bit devices, meaning that developers are able to limit their apps to more recent hardware. The iPhone 5C is now the only iOS device in Apple's current lineup without 64-bit support.