These docs are for an old release.
Info on upgrading to version 2/3
eventBackgroundColor
Sets the background color for all events on the calendar.
String
You can use any of the CSS color formats such #f00, #ff0000, rgb(255,0,0), or red.
This option can be overridden on a per-source basis with the backgroundColor Event Source Object option or on a per-event basis with the backgroundColor Event Object option.