The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Exact Editions:
Increased the resolution of pages you choose to share. Added option to log in with your Exact Editions username and password. This replaces the old Shared Access Code approach, though if you have already logged in using a Shared Access Code you won't need to log in again. Fixed a problem with push notifications. Tweaked icons and artwork. Minor bugfixes.