Devices with the iOS operating system version 4.3 or higher do not support client-based (device-based) positioning via Wi-Fi. Apple relies exclusively on iBeacon technology for indoor positioning. This means that a client-based indoor navigation project that works exclusively with Wi-Fi would exclude all Apple devices. To provide indoor navigation for all devices, the system should work with beacons. However, server-based detection - for example, to measure visitor flows - is possible under iOS using either beacons or Wi-Fi.