I had an update function in software I wrote. IT worked great for the
people in my time zone. It would check a file on a server and a file on
their computer and if it appeared earlier than the update it would
download to them.

However, I actually got a customer out of my time zone. The result was
for the next hour it kept prompting them to update.

My question is how could I detect the time zone and account for it in
checking with a file on a server to verify if they need an update?

Thank you for your help.