In Japan, the Sony Xperia Z4 is the latest device from Sony, but it's called the Xperia Z3+ elsewhere. Why is that? Sony recently revealed its reasoning for the name change in other markets. It's because the device doesn't change enough to justify calling it a brand new device compared to the Z3, and consumers would respond better to thinking it's a slight upgrade of the Z3 rather than a brand new Z4. That's pretty smart if you ask me.