These docs are for an old release.
Info on upgrading to version 2/3
monthNamesShort 1.3
Abbreviated names of months.
Array, default:
['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun'
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
Prior to version 1.3, this was possible by setting $.fullCalendar.monthAbbrevs