With this method: Dim f As Aspose.Cells.FileFormatInfo = Aspose.Cells.FileFormatUtil.DetectFileFormat("really_old.xls") I am able to detect f.FileFormatType = FileFormatType.Excel95 I realize your product inf…...Detecting old excel file formats Aspose.Cells Product Family...Aspose support. Other than the file format, Aspose.Cells API can...