In 2025, the University of Rostock has the great honor of hosting the 21st International IEEE Conference on Factory Communication Systems (WFCS 2025). The WFCS is the only IEEE conference dedicated specifically to communication for industrial automation systems. It will take place in Rostock for the first time. The conference will be hosted by Institute of Applied Microelectronics and Computer Engineering (IMD) of the University of Rostock (Germany) and organized in collaboration with Institute of Electronics, Computer and Telecommunication Engineering CNR-IEIIT (Italy). The WFCS is supported by IEEE and IES and coordinated by the IEEE TC on Factory Automation. The local organizers University of Rostock, Faculty of Computer Science and Electrical Engineering and IMD invite all interested parties to participate in this exciting event and exchange ideas with international experts. The conference will take place between June 11 and 13, 2025 in the main building of the university in the heart of the city of Rostock.