On the one hand, mobile devices in the form of smart phones and tablets in addition to thin, modern-generation laptops and wearables are increasingly making their way into the business world and changing the way we work. On the other hand, the companies producing those devices and their respective software stacks create their own silos, with their own tool chains and their own ideas of how the user should interact with those devices. And then along comes Qt! A common user experience, making use of unique features of each type of device where necessary, is now possible, regardless of who made the device. Just what the world of BYOD (bring your own device) needs. However, getting there is not easy. This talk takes a look at mobile systems on the basis of iOS and Android, and on Windows-based systems, focusing on an adaptive approach to designing and to building applications and managing their data, using a language instruction system as an example.