This paper presents ongoing work focused on dynamic reconfiguration of industrial automation systems as a part of their total life cycle. Modification of the control logic has to be enabled at runtime and without any disturbances of related applications. The εCEDAC engineering cycle for dynamic system evolution is based on the use of an IEC 61499 reconfiguration application responsible for the dynamic transformation of the program during its execution. The verification of this evolution step takes the central role in this engineering cycle. The paper discusses the general requirements for this kind of verification. Especially the capabilities of the automation system-the used hardware and software-form a major point. The paper describes the basic concepts and ongoing work regarding the verification of downtimeless system evolution.