Originating in 2011, Industry 4.0 describes the digital revolution of industry and has since become a collective term for smart, mutable and data driven factories. During the last decade systemic and methodical solutions were designed and implemented that enable corresponding data driven use cases for producers. Today's system providers offer complex data ecosystems in which data-driven use cases are built-in and implementers offer focused digitalisation projects to rapidly address quick wins. While an assessment of expectations around Industry 4.0 results in requirements within the domains of modifiability, connectivity, data and organisation for an IT-architecture, many such solutions are found to be violating essential requirements as systemic flexibility and data-availability. Not only is this a relevant matter for architectural purists, but it highlights real problems that industry is still facing while applying digitalisation measures in pursuit of Industry 4.0.While event-driven architectures go back to the design of modern operating systems, the emergence of powerful, resilient and cheap broker-technologies has risen the polarity of event-driven IT-architectures for businesses in the last decade. Although its occurrence is predominantly represented in ecommerce, finance and insurance, many prominent manufactures have since begun their transformation into an event-driven IT-architecture. Reasons for this architectural adaptation include exceptional data availability, resilience, scalability and especially data sovereignty. An assessment of event-driven IT-architecture's properties and implications reveals an excellent fit for the architectural requirements of Industry 4.0.In this work the subject of Industry 4.0 is analysed along literature to derive a collective understanding of expectations from a factory implementing Industry 4.0. Subsequently, IT-architectural requirements are derived that describe an architecture capable of satisfying these expectations. Then event-driven IT-architectures are analysed regarding their structural composition and capabilities. Finally, the fit of event-driven IT-architecture is evaluated against the architectural requirements of Industry 4.0, discussing congruence and divergence.