I am running Mac OSX Snow Leopard and as a consequence I am receiving notifications that Safari needs to be upgraded in order to view the web page properly. "your version of Safari is no longer supported by our website or webpage". How do I upgrade Safari? Do I have to upgrade the OSX and if so how do I do that? My sense is that a jump from Snow Leopard to Yosemite to too large a jump and this upgrade may have to be incremental. What is your advice? The computer is an iMac...approximately 5 years old.