We investigate the ways in which information system upgrading affects user performance and its contextual variance. Using expectation disconfirmation theory and cognitive dissonance theory, we explain why performance dip typically occurs in technology implementation. With one study each in a voluntary usage and a mandatory usage context, we find that the performance dip related to negative disconfirmation of user belief in the usefulness of a new system is more penetrating in the mandatory usage context. Our research sheds light on ways to alleviate the negative repercussions of technology implementation and to upgrade systems successfully. It also has important implications in the post-COVID-19 era, as telework and system upgrades become commonplace.