One of the major challenges that SMEs (small and medium enterprises) face when it comes to the implementation of Industry 4.0 is the high technological complexity and consequently the high investment and operation cost to be expected as well as the need for highly qualified specialists to operate and maintain such complex systems. This paper presents a generic CPPS (cyber-physical production system) architecture that copes with SMEs specific challenges and simplifies the implementation of the Industry 4.0 paradigm in real world applications. The proposed CPPS architecture has been validated in an industrial pilot application. The COSMIXER-CPPS is able to control devices with different interfaces and protocols as well as to communicate with external databases and web-services. The unified communication middleware within the CPPS enables furthermore the reconfiguration and scaling of the system with minimal disruption. This research is a contribution to reduce inhibitions towards the implementation of Industry 4.0 in SMEs, further research has to be carried out to investigate and enhance the dependability, security, real-time capability and performance of SME-friendly CPPS.