The hard part is finding a device that can run 4.3 for testing. Technically, you could launch an app that supports iOS 2 or 3 all the way to iOS 7, the hardship

The hard part is finding a device that can run 4.3 for testing. Technically, you could launch an app that supports iOS 2 or 3 all the way to iOS 7, the hardship is testing! Unlike Android post-Froyo, Apple's emulators have never been that accurate. in both cases, memory and device limits on older hardware become the significant bottlenecks. That and with every OS X update you lose another simulator major version each year. Typing from memory, so I could be wrong: 10.6 had everything. 10.7 lost 3.x, 10.8 lost 4.x and 10.9 lost 5.x simulation. I had to install VMs to run emulators, how sad is that? All this would be fine if Apple allowed developers to downgrade as post-Xcode 5 hinted, an option removed when the jail breaking started.