PLEASE use the built in AppStore application to update applications.
iTunes frequently installs old versions.
Please see Q10 in the FAQ.

The old SkyCharts Classic (the $9.99 version) will today start asking you to update to the Pro version. If you have been onboard since the beginning you may have had up to 3.5 years of current charts for $9.99!!!

In order to keep getting current charts, please purchase the Pro version of the application.

If you think you’re getting the upgrade message in error, please see the contact tab.

There is never a good time for this…
Server should be back up in about 1hr.

Update: 10.43pm PDT. Server now back again.