A team of developers is tasked with developing an enterprise application. They have interviewed stakeholders and set a scope of work that will deliver a subset of the functionality needed. Developers and stakeholders have identified risks and ways of mitigating them. They then proceed to gather requirements for the subset of functionalities to be implemented. That is followed by design, implementation, and testing. There is no collaboration between developers and stakeholders until after testing, when developers review results with stakeholders and plan the next iteration of development. What application development methodology is this team using?