Safari browser causing issues with uploads

Clients that use the Safari browser are often unable to upload documents or fully use the portal simply due to the browser and it isn’t a particularly good look from a technology point of view to have to tell them to use Chrome or Firefox as a workaround. They can’t see how advanced BGL360 as a whole is; but they do see this relatively simple (in their eyes) issue as a shortcoming in the program we are using. If the underlying issues that are causing this incompatibility could be addressed that would be greatly appreciated. Thank you