Adding dayNameShort inline calendar does not display

Im having problems on how to add the dayNamesShort on the calendar.

 var resp = response.response;
                var calendarInline = app.f7.calendar({
                    container: '#calendar-inline-container',
                    value: [new Date()],
                    weekHeader: false,
                    color: '#ff0000',
                    dayNamesShort: ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'],
                    events: (function () {
                        var events = [];
                        for (var i = 0; i < resp.data.length; i++) {
                            events.push({
                                from: new Date(resp.data[i].start),
                                to: new Date(resp.data[i].end),
                            })
                        }
                        return events;
                    })(),
                    toolbarTemplate:
                        '<div class="toolbar calendar-custom-toolbar">' +
                        '<div class="toolbar-inner">' +
                        '<div class="left">' +
                        '<a href="#" class="link icon-only"><i class="icon f7-icons jj-icon-color">left</i></a>' +
                        '</div>' +
                        '<div class="center"></div>' +
                        '<div class="right">' +
                        '<a href="#" class="link icon-only"><i class="icon f7-icons jj-icon-color">right</i></a>' +
                        '</div>' +
                        '</div>' +
                        '</div>',
                    onOpen: function (p) {
                        console.log(p)
                        $$('.calendar-custom-toolbar .center').text(monthNames[p.currentMonth] + ', ' + p.currentYear);
                        $$('.calendar-custom-toolbar .left .link').on('click', function () {
                            calendarInline.prevMonth();
                        });
                        $$('.calendar-custom-toolbar .right .link').on('click', function () {
                            calendarInline.nextMonth();
                        });
                    },
                    onMonthYearChangeStart: function (p) {
                        $$('.calendar-custom-toolbar .center').text(monthNames[p.currentMonth] + ', ' + p.currentYear);
                    }

Must be

weekHeader: true