Sub wkbkSave()
Dim xlVersion As String
Dim myxlOpenXMLWorkbook As String
myxlOpenXMLWorkbook = "51"
xlVersion = Application.Version
Select Case xlVersion
Case Is = "9.0", "10.0", "11.0"
ActiveWorkbook.SaveAs FileName:="LegacyVersionExcel.xls"
Case Is = "12.0"
ActiveWorkbook.SaveAs FileName:="Excel2007Version", _
FileFormat:=myxlOpenXMLWorkbook
End Select
End Sub