Question: Does the Calendar App account for the 10 days that were omitted when the Julian calendar transitioned to the Gregorian calendar?

Answer: Pope Gregory, after being advised by Jesuit astronomer, Christopher Clavius, dropped 10 days from the Julian calendar in 1582 when promulgating what we today call the Gregorian calendar.  The last day of the Julian calendar was Thursday, October 4.  The following day was Friday, October 15, and was the first day of the Gregorian calendar.  The weekly cycle was in no way affected by this transition.  It is important to note, though,  that the Julian calendar originally had an 8-day week, like that of the Republic that preceded it.  Unlike the Hebrew calendar, the Roman calendar had a continuous weekly cycle.  (For more on the fallacy of the modern weekly cycle, refer to "Continuous Weekly Cycle" Proven False.)

The WLC Calendar App does not show the omission of days in 1582 because the Calendar App's algorithm is designed only to reach as far back as 1601 AD.  Putting a cap on the application's ability to dig indefinitely into the past was necessary in order to keep the app lightweight and functional.  Pope Gregory's omission of days in no way affects the accuracy of the app's forecast.  The moon pays no attention to any of man's inventions, including the papal Gregorian calendar.