The introduction of new technologies opens a wide range of new possibilities; however, it also leads to new challenges that need to be addressed to fully exploit the potential of such technologies. The identification of the barriers and challenges that preclude the adoption of Industry 4.0 helps identify solutions in the early stages and promote its establishment. One of the major problems facing the new technological paradigm is the lack of interoperability between heterogeneous systems.An initial step to solving this problem is the accurate identification of the interoperability mismatches between systems that preclude the consumption of services. This paper proposes the service contract as the main element in the definition and identification of interoperability problems that can occur in SOA-based heterogeneous environments. The presented approach modifies the traditional service contract viewpoint and introduces a new reformulation of the concept to adapt it to current technological requirements. The new service contract concept can be used as a core factor in the identification of interoperability mismatches at the service interface level. Problems related to the current definition of a service contract and potential solutions are introduced and discussed.