Well that was fast. Apple's new iPad just went on sale this morning, and developer Marco Arment has already released a 4.1 update to his popular reading app Instapaper that provides Retina display support for the new device. To make reading even easier on the iPad's 2048 x 1536 display, the free update includes a set of six new fonts, including Proxima Nova, FF Tisa, and the new default, Elena. A full-screen reading mode is now also included, and the app's "Automatic Dark Mode" — which switches the app's color scheme after sunset for an easier reading experience— has been updated with a sepia-toned mode for early evenings and mornings.

According to Arment, the update was submitted just today, and he wasn't expecting it to be available for several days. The App Store's review team appears to be burning the midnight oil, however, which is great news for Instapaper users — and for everyone that's opening up a new iPad today. Instapaper 4.1 is available for download now.