Over the last 4 years the (real-time) Attribution team at Appsflyer has been successfully evolving the same set of micro-services. However, for a long time the engineering team has felt the attribution flow has "unfixable" flaws, AKA technical debt, A complete re-write was decided upon, with a totally new architecture design: a risky, bold decision. In this session, I'll describe the rollercoaster process of harnessing the entire organisation (R&D and business) with the development and risky migration process of all our traffic and customers to a completely new set of attribution micro-services. we'll cover the good and bad decisions made, and the agility needed from everyone to succeed