Goodbye Mac OS X and hello macOS Sierra. Apple announced at WWDC 2016 that its new operating system for its Mac computers and MacBook laptops has been given a new name – and a lot of exciting new features, and if you can now download and install macOS Sierra right now.Apple usually releases updates at 10:00 PDT (13:00 ET, 18:00 BST, 03:00 the next day...