I am converting xslx to xls

This is my code

oXL = CreateObject("Excel.Application")
oXL.Workbooks.Open("c:\citisprint\attachxls\latest.xlsx")
oXL.ActiveWorkbook.Saveas("c:\citisprint\attachxls\latest.xls", 39)

Conversion works fine except that the date in the xslsx file of 24/10/16 gets converted to 42667 in the xls file

Any ideas

Colin