I make use of CultureInfo.OptionalCalendars in order to support both Gregorian calendars and others, such as the Hijri and Hebrew calendars.
On Windows platforms (UWP desktop, UWP phone, WinRT 8.1, WinPhone 8.1 RT) I find the expected calendars available in CultureInfo.OptionalCalendars.
However, on Android and iOS devices, OptionalCalendars only ever contains one calendar. Can anybody tell me what I need to do in order to get more than one calendar in the OptionalCalendars collection ?