I had the opportunity to use two different date format versions of this program. They both worked perfectly and the company immediately answered me with by email if I had any questions. I easily altered the asp pages to better fit my business. I put the appointment book on a win 2003 server and connect to it from four different computers. I highly recommend this appointment book if one column of up to 5 minute appointments per day will fit your business and you have an asp page server.