Week start day
I have received a lot of very positive feedback for my new calendar picker, however a number of people have also asked for the week start date to be configurable. My app has always used Monday as the start date for entering dates, but I can understand that some people would prefer (e.g.) Sunday.
My calendar picker was written with any day in mind, and there is even a setting in the main settings app that I could use (under “Mail, Contacts, Calendars” at the bottom). However there doesn’t seem to be a way to access this setting from within an app. I even have code for this that works fine on OS X but doesn’t on iOS. I have therefore opened a bug against iOS.
If Apple come back with a workaround to this issue, I will happily support the day you choose in the settings app.
UPDATE: no response from Apple after a month. I will probably add my own setting for this in my next update.