With just a day to go before Apple’s new mobile operating system is officially released, Barnes & Noble has notified users of its Nook iOS app about a couple of issues that they may encounter on iOS 7.

Unlike Amazon, which already issued a pre-iOS 7 update for its Kindle iOS app last week, Barnes & Noble is still working on an update that will provide full iOS 7 compatibility for its official e-reading app on iOS. Apparently, the update hasn’t been completed in time for the launch of iOS 7 tomorrow.

But the company has discovered a couple of short-term issues that users might encounter with the app on iOS 7. And it has warned users about these via email.

According to the email sent by Barnes & Noble’s Nook team earlier today, one of the issues has to do with screen rotation and the other has to do with account sign-in:

  • If you rotate the screen while reading, it may cause the page to render incorrectly or may cause the app to crash. To prevent this, we suggest locking the rotation while reading.
  • If you sign out of your app and then sign in again, the app may crash or you may have trouble accessing your Library.

“Please note that not everyone will experience these issues,” the Nook team adds. “And for those who do, be assured we are working as quickly as we can to resolve them.”

Nook for iOS is available in the App Store as a free universal app.

The app received its last major update back in March. That update added support for Nook Comics with ZoomView, animated page turns for books, enlargement of book illustrations, and other improvements.

Last month, Barnes & Noble launched Nook Video for iOS. The Nook Video app lets users watch movies and TV shows from Barnes & Noble’s Nook Video service right on iPhone, iPod touch, or iPad.