Made the mistake this evening of starting to look at the possibilities when it comes to updating the operating system on my macbook.
Turns out that the latest is called Mavericks, soon to be replaced by Yosemite (looks like they might have run out of big cats?). Not entirely sure yet what it does that my Lion isn't doing, other than take up space no doubt, which is fairly precious these days on my 64GB solid state, but may have to continue investigation at later date.