Safari Update

As to your question, Safari, being installed as part of the operating system, normally it cannot be individually upgraded. it is periodically updated when the computer's operating system is updated or upgraded. This is not an unusual complaint. Web site engineers write their software to work with specific browsers. For some reason, they often choose to not be compliant with Safari, or are late in updating their web sites. This is not an Apple problem as Apple has no control over the millions of web sites on the internet. You can hope that your web site's developers eventually update their site to work with Safari, or you can use another browser that does work, such as Firefox or Chrome.

If by chance Safari is an old out of date version, then you will need to either update your computer's OS or upgrade to a newer version.