Settings

UI

Calendar, date formats, theme and color options.

Settings > UI is display only.

Settings, UI: calendar, date and time formats, and the theme

Setting	Choices
First Day of Week	Sunday or Monday (Monday by default). The Calendar grid and week view follow it
Week Column Header	`Tue 3/25`, `Tue 25/3` or `Tue Mar 25`
Short Date Format	`Mar 25 2014`, `25 Mar 2014`, `03/25/2014`, `25/03/2014`, `2014-03-25`
Long Date Format	Four layouts, with or without the weekday
Time Format	12-hour or 24-hour
Show Relative Dates	Today and Yesterday instead of dates
Theme	Auto (follows your OS), Light or Dark
Enable Color-Impaired Mode	Alters the color coding so statuses are easier to tell apart

The defaults are in the app. These settings are shared by everyone using the instance.