Hello MAUmal51,
Thank you for using Apple Support Communities. In order to be able to update Safari, you will need to update your macOS. New macOS updates include updates for Safari and other features. This resource does explain more: Update to the latest version of Safari - Apple Support
If you confirm there are no more available updates for your Mac, there is a possibly that you might have already reached the highest compatible version of macOS your MacBook Pro can support. If this is the case, you won't be able to update Safari any further.
If an update or upgrade isn't compatible with your Mac, it doesn't appear in Software Update.
If this is the case, you might need to use a third-party browser.
We hope this helps out. Thank you for using Apple Support Communities.