In this phase, the key is to understand if your problem is caused by technology, architecture or functionality of the application, and how each modernization approach improves those aspects.
Gartner predicts that every dollar invested in digital business innovation through to the end of 2020 will require enterprises to spend at least three times that to continuously modernize the legacy application portfolio.
Spending that money effectively will require application leaders to carefully select one of the seven different modernization approaches.
A new framework defining different migration strategies that organizations can apply on applications before migrating them to cloud is called R-Lane. Gartner defined 7 R strategies (Rehost, Re-platform, Re-factor, Re-Architect, Replace) to follow while migrating application workloads to the cloud.
Joseph's Cloud Notes 