With Estimote Indoor Location, we're tightly integrating software and hardware to make it easy to add precise location to any iOS application.
Since the hardware part is as important as the software one, our Indoor Location is currently tuned around iPhone 5, 5C and 5S—these models will provide you with best location accuracy. Other Bluetooth Smart enabled iOS devices will work, but the positioning accuracy may vary.
We're already hard at work to bring more of the tight Indoor Location tuning to other iPhone devices, including iPhone 4S, 6 and 6 Plus, and iPad tuning will follow shortly thereafter. Stay tuned for the upcoming versions of Indoor Location!