The exponential growth of Internet of Things (IoT) sensors and data has led to multiple software applications which aim at collecting, monitoring, controlling, and automating decisions based on such data in several domains such as smart cities. Even though early IoT frameworks and software architectures relied on correlating data from a single application domain, missing opportunities to improve contextualisation; in the last years several Complex Event Processing (CEP)-based frameworks and applications have been provided to improve the correlation of data from heterogenous domains, facilitating context-aware decision making. However, several issues remain unsolved: on the one hand, frameworks should not only provide the means for data correlation and contextualisation, but also for the definition of customisable real-time actions based on the context. On the other hand, CEP patterns update remains static in these frameworks, while there is a need for dynamically updating CEP pattern logic to adapt to changing contexts in real time. Even more, CEP patterns logic understanding might also be a handicap for developers. To face these challenges, in this paper, we enhance an existent CEP-based framework and software architecture by incorporating Business Process Modelling (BPM) to facilitate the definition of CEP patterns rationale, manage interdependencies between patterns, define and handle contextualised user actions, and enable real-time updating of CEP pattern logic based on detected situations. The proposed approach is illustrated through a case study, assessed via usability and performance evaluations, which show improvements in comprehensibility, maintainability, and updatability of CEP-based software applications for context-aware IoT scenarios.