When choosing consumer goods, it is important for today’s customers to be able to express their individuality. This social trend has also reached the automotive industry, which is why users can choose from a long catalogue of additional equipment when buying a new vehicle or even tailor it entirely to their individual preferences. However, the defined range of functions cannot be changed subsequently, unlike a smartphone, which can be constantly adapted to current demands thanks to regular software updates and an almost infinite app store. To meet these customer needs, a highly adaptable HMI system, which can be modified by users at any time to the changed demands is beneficial. In addition, new, temporary services and functions should be provided to the customer as an after-purchase offering, allowing for continuous improvement of user experience. If OEMs pursue the technology strategy of an on-demand customizable HMI system, they can take advantage of new revenue and monetization opportunities and also reduce their product variety by standardizing hardware as much as possible and shaping product variety through after-purchase features.\r\nThe realization of such an on-demand customizable HMI system requires over-the-air updates. An enabler for this is a software-defined vehicle, which entails an abstraction of the software from the hardware level. In order to facilitate the implementation of new software packages, a modular software architecture is favorable, in which individual modules can be replaced or extended. However, an abstraction of software and hardware not only has advantages for software updatability, but hardware can also be adapted to technological changes for new vehicle models. For example, new sensors for in-cabin sensing can be implemented without the need to adapt the complete software stack, only by extending the corresponding software package. \r\nAn approach for such a modular structure is the service-oriented architecture (SoA), in which software is divided into small, self-contained modules (services) that can be updated individually. SOAs are considered as one of the key elements for more flexibility, integration of external services and on-demand functions. Each software function is split into a different service that can be integrated during runtime. This allows services to be modified after completion of the design process, including function updates, replacements and reuse. In addition to improved updateability, an SoA also offers security-related benefits. If a hardware element fails or resources are insufficient, functions can be moved flexibly to other hardware elements. This means that in addition to better updatability, greater robustness and reliability can also be achieved. However, with the implementation of a SoA, new challenges also arise, for example, with regard to existing security measures, because dynamic communication is more complex to secure as it changes over the runtime. \r\nIn this talk, I will discuss the opportunities and challenges OEMs and suppliers face by implementing a modular software architecture to enable easy updateability of vehicles. In addition to technical possibilities and challenges, I will discuss future software architecture changes to meet dynamically changing requirements for HMI systems.