iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Apple Sells Two Million Copies of Leopard in First Weekend
"Early indications are that Leopard will be a huge hit with customers," said Steve Jobs, Apple's CEO. "Leopard's innovative features are getting great reviews and making more people than ever think about switching to the Mac."
According to ArsTechnica, it took Apple a month to sell 2 million copies of Mac OS X Tiger -- the previous release of Mac OS X. Leopard launched officially on Friday, October 26th at 6 p.m.