This dissertation discusses the evolution of interpersonal communication from the traditional era to the digital era, which has been influenced by technological developments, particularly in the context of messaging applications such as WhatsApp. Initially, the Expectancy Violation Theory proposed by Burgoon in the 1970s only focused on face-to-face communication, but with the advancement of technology and the internet, interpersonal communication has expanded to include digital media and a new term has emerged, namely mediated interpersonal communication, making it an interesting subject of research. The author explores the theoretical understanding of the forms of expectancy violation that occur among millennials in mediated interpersonal communication. The dissertation also attempts to identify the forms of expectancy violation that occur in mediated interpersonal communication, the factors that influence the occurrence of expectancy violation, and the reasons for expectancy violation. Through the study, the author found that confirmation and violation of expectations in text messaging often occur in everyday interactions. This research also highlights changes in communication norms and ethics that occur alongside the penetration of technology into daily life. Although traditional norms and ethics are still relevant in face-to-face communication, the use of technology such as WhatsApp has changed these dynamics, causing miscommunication and new challenges understanding messages accurately.   In conclusion, the evolution of interpersonal communication toward the digital era, particularly through messaging apps like WhatsApp, has altered norms and ethics in communication. This research highlights how the development of information technology triggers the confirmation and violation of expectations in daily interactions, marking a shift in how individuals interact and understand one another. Additionally, it is important to note that the presence of various new messaging platforms brings its own characteristics, which in turn makes the form, factors, and reasons for confirmation and violation of expectations different. This reflects how information technology has become an integral part of the dynamics of modern interpersonal communication, adapting to evolving communication needs and creating new challenges in accurately understanding messages.