I am told my version of Safari (v6.1.6) is out of date and needs to be updated to make more secure. Following the links I see in the app store I have one upgrade to download. However when I attempt to download it says I cannot install it on my iMac, but I read it can be used on all OS after 10.6. I am running 10.7.5 on a 8 year old iMac with increased memory. So why can't I install it? If my iMac is too old why does it recommend it? Thanks.