A system upgrade requires careful planning as its implications to organizational systems might beenormous. Although in IS literature the requirements and process of systems upgrade have been discussed,the timing when to upgrade and what factors guide it has been of lesser interest. Consequently,in this paper we focus on information systems upgrading and its timing from the perspectiveof the user organization. Upgrading is enabled by the availability of a new software version. When toupgrade, meanwhile, is determined by the business interests of the customer organization, businesscalendar, development projects, and the vendor. These factors were identified by interviewing 14 ITmanagers, mainly CIOs, from middle size to large organizations in Finland. They presented 16 differentcases of upgrading or modifications of enterprise systems or similar undertakings. The analysis ofthe cases and the identification of the upgrade timing factors not only increase our understanding ofthe phenomena in general, but also reveal the customer’s motives and interests regarding IS upgradingand its timing
