This looks great but can result in some parts of a window being opaque and others partly see-through, which can be confusing. Now, there's greater translucency to drop-down panels to show the colours behind more clearly. And Yosemite has taken a lot of the design language from the handheld. It's all gone through the rigorous updating that the iPhone 5s went through last year with the move to iOS 7. One of the most immediately striking changes in Yosemite is the OS design. This kind of synergy is brilliant, and requires the two systems to be in synchronised step. One of the stand-outs announced at the World Wide Developers' Conference in June was a system where you could start writing an email on your iPhone but then, when you realised it was going to be something of a magnum opus, carry on with it seamlessly on your Mac - whether it's an iMac, MacBook Air or MacBook Pro. Perhaps we can expect new features to launch on both phone and laptop almost simultaneously.

The two separate systems now overlap so much that it makes sense to update them both at the same time. And since last year OSX has had an autumn update, too.

Apple users are familiar now with the annual update cycle: the software for the iPhone, iPad and iPod touch are updated each autumn.

What is mac os yosemite