updated 05:35 pm EST, Wed February 15, 2012
Early pre-order titles no longer need art
Apple has issued a letter to iBookstore publishers, informing them of several small but significant upgrades to the storefront. The first is support for screenshots, which Apple recommends using for "Fixed Layout, Read Aloud, and Multi-Touch books." The change was likely made with Apple's interactive textbook initiative in mind.
Publishers can now also get up to 50 promo codes for each book, mirroring an option available to App Store developers. For pre-orders, Apple has begun accepting submissions without covers or book assets, but only up until two weeks before publication. At that point a title must have a cover, assets, and a custom preview.