- `default`: accepts a datetime string, or an empty string to accept blank input; otherwise defaults to current datetime
- `format`: sets storage format; accepts Moment.js [tokens](https://momentjs.com/docs/#/parsing/string-format/); defaults to raw Date object (if supported by output format)
- `date_format`: sets date display format in UI; boolean or Moment.js [tokens](https://momentjs.com/docs/#/parsing/string-format/). If `true` use default locale format.
- `time_format`: sets time display format in UI; boolean or Moment.js [tokens](https://momentjs.com/docs/#/parsing/string-format/). If `true` use default locale format, `false` hides time-picker.
- `picker_utc`: _(default: `false`)_ when set to `true`, the datetime picker will display times in UTC. When `false`, the datetime picker will display times in the user's local timezone. When using date-only formats, it can be helpful to set this to `true` so users in all timezones will see the same date in the datetime picker.