Java Programming

Hi

I am trying to make a very small report in HSSF apache poi.
I have set following content type in servlet code.

OutputStream out = response.getOutputStream();
				response.setContentType("application/vnd.ms-excel");
				response.setHeader("Content-disposition","inline; filename=report.xls");
				wb.write(out);
				out.flush();
				out.close();

Now I wish to know that if Excel is not installed in machine where this application will run and user directly saves it suppose with name "download.xls"
Then this xls document is saved in compatibility to which version of Excel.

Thanks.