PostprintThis is the accepted version of a paper published in International journal of business information systems. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.Citation for the original published paper (version of record):Magnusson, J., Nilsson, A. (2013) Introducing app stores into a packaged software ecosystem: a negotiated order perspective. Abstract: This study addresses the emerging phenomena of app stores for packaged software such as enterprise resource planning (ERP) and customer relationship management (CRM) systems. Through employing the technology of app stores, ERP and CRM vendors have been reported as shifting from delivering software as a service (SaaS) to platform as a service (PaaS). Through an in-depth case study of one ERP vendor's app store initiative, the study identifies and discusses instances of negotiated order of the ecosystem. The results show that the introduction of an app store for ERP brings with it the threat of restructuring both the incumbent business model and the power relationships nested in the ecosystem, thus spurring intensified instances of negotiated order. This is discussed in terms of different arenas of conflict for negotiated order.