When aging applications aren't compatible with the cloud, they might need to be rearchitected to produce cost and operational efficiencies in the cloud.
Unsupported, misaligned, or out-of-date on-premises applications might be too expensive to carry forward. A new code base with a cloud-native design might be the most appropriate and efficient path.
Sometimes the best approach is to replace the current application with a hosted application that meets all functionality required in the cloud.