“Where art thou, Nook?” I asked in conclusion to my post about the long overdue Retina iPad update for Kobo. Well, Nook responded mere hours following my rhetorical question.

Version 3.1.3 of Barnes & Noble’s Nook app for iOS is now live in the App Store. As expected, the update bestows Retina text and graphics upon the app, thereby making it adequate for the new iPad’s screen. Gone are the blurry words and even blurrier images on the Nook books downloaded on your iPad.

Speaking of downloading Nook books, some users are apparently experiencing some trouble in this regard after installing the update. In fact, I am one of those users. Every time I try to download a book into my newly updated Nook app, a dialog message appears alerting me that my credit card information is out of date. Barnes & Noble recommends logging in to the Barnes & Noble website to make sure that the credit card set as the default mode of payment is valid. I have done this, but it still doesn’t solve the annoying glitch. In any case, the validity of the credit card associated with your Barnes & Noble account shouldn’t be a prerequisite for downloading books that you have successfully bought in the first place. Neither Apple’s iBooks nor Amazon’s Kindle requires such a step for downloading previously purchased books, and I don’t see why Nook should.

The new Nook update alerts some users about updating their credit card info before they can download books.

But back to the update… The new version of Nook also allows one- or two-column view when reading in landscape mode on the iPad, new or not. The highlighting feature for both iPad and iPhone versions of the app has also been improved, letting you highlight as many words as you want. And, of course, some unspecified and hence minor bug fixes are also included in the update.

The update is free and requires iOS 4.3 or later. It’s compatible with all iPad models, iPhone 3GS/4/4S and iPod touch third generation and up. Nook is available in the App Store for free. Glad to have you on board the Retina iPad bandwagon, Nook, but please fix that credit card nuisance soon.