After an update of our website ( running on Apache ) we get some issues with .js files images ect ... It seems that old files were mixed up with new one. My question is how cache works ? Do we have to restart Apache each times we perform an update ? How Firefox know / handle new files from a website ? Thanks!
The caching mechanism is different for every browser. If you would like more information regarding browser caching, I would suggest a post to Superuser.
For Apache, there is not native caching functionality within the server for static content.