Refresh php page after updating xml file to be parsed by that page

I found that contents parsed with simplexml in a php page doesn't refresh when I load an updated xml file, On the pc refreshing manually the page works and it gives me updated contents, on my mobile phone (HTC One M7/Chrome for Android) it doesn't work.

I tried header("refresh: tempo;"); and $_SERVER['PHP_SELF'] inside the page but they don't work.

Have you got any idea?

Thanks