Planning the next release in software release planning addresses the problem of assigning features to the next release such that technical, resource, risk, and budget constraints are met. This paper studies the planning for the next release of an evolving system from a bi-criteria perspective. We introduce a method called NRP-trade-off to adjust baseline release plans for more modifiability by replacing lower value features with features having a higher modifiability. For that purpose, we include a new approach for feature modeling and assessing modifiability by applying object-oriented design metrics to the feature domain. We also briefly introduce a case study.