MQTT messages let TeslaSCADA2 Runtime applications for Windows, Linux, MacOS, Android and iOS connect to TeslaCloud by using MQTT client and get data from it. It's better to use direct TeslaCloud client because it's faster and use reactive protocol for the same purposes. TeslaCloud client is available on Windows, Linux, MacOS and Android versions. But it's not available on iOS version. So for iOS version of TeslaSCADA Runtime you can use MQTT client for connecting to TeslaCloud. It's possible to use MQTT API for third-party applications, but for these purposes you have to carefully study protocol messages below.