Packaged software is widely adopted and has become an integral part of most organizations'' IT portfolios. Once packaged software is adopted, upgrades to subsequent versions appear to be inevitable. To date, research on packaged software upgrade has not received the attention that it warrants. To explore this understudied yet important area, three research questions were proposed: (1) What influences the decision to upgrade packaged software? (2) How do stakeholders cope with software upgrade? (3) How does a packaged software upgrade affect stakeholders? Two cases were conducted at a Fortune 500 company located in the Southeastern region of United States. A theoretical model with six components was induced from the study; the components are decision, motivating forces, contingency forces, planned strategies, corrective actions, and impacts. The findings in this book should benefit anyone who is interested in understanding decisions, impacts, and coping strategies of packaged software upgrades.