Telcos are looking for opportunities to respond to market pressures from customers, market disruptors (5G slicing, MVNOs), and advances in technology (AI, cloud-native solutions). Operational Support Systems (OSS) and Business support systems (BSS) are core systems within telcos which support capabilities across the value chain and a foundational enabler to position telcos to respond to these market pressures. CIO tasked with modernizing legacy OSS and BSS need to consider the scope and pace of their modernization efforts all the while minimizing impact to day-to-day business operations. This research aims to provides CIO considerations when deciding on an overall OSS/BSS modernization strategy.