As per your existing application analysis, you can take a different approach to upgrade your legacy system. The most straightforward approach will be migration and rehosting, where you don't need to make many changes in the existing system. However, a simple migration may not solve the long-term problem or provide a benefit. You can take a more complex approach, such as rearchitecting or redesigning the entire application if the system is no longer meeting the business need. The following diagram illustrates the effort and impact of the various methods:

Let's look in more detail at the various modernization techniques shown in the preceding diagram.