ajaxcontroltoolkit.calendarextender does not have a public property named DaysModeTitleFormat

<asp:TextBox ID="TextBox2" runat="server" Width="118px" ontextchanged="TextBox2_TextChanged" TodaysDateFormat="dd/MM/yyyy"></asp:TextBox> <ajaxToolkit:CalendarExtender ID="TextBox2_CalendarExtender" runat="server" Enabled="True" PopupButtonID="ib1" TargetControlID="TextBox2" DaysModeTitleFormat="dd/MM/yyyy" Format="dd/MM/yyyy" > </ajaxToolkit:CalendarExtender>

ajaxcontroltoolkit.calendarextender' does not have a public property named 'DaysModeTitleFormat'

how it will be removed??????