Looking at legacy system modernization techniques
As per your existing application analysis, you can take various approaches to upgrade your legacy system. The most straightforward approach is migration and rehosting, where you don't need to change the existing system. However, a simple migration may not solve the long-term problem or provide any benefits.
You can take a more complex approach, such as rearchitecting or redesigning the entire application if the system no longer meets business needs. The following diagram illustrates the impact of the various methods:
Figure 17.4: Legacy system modernization techniques
Let's look in more detail at the various modernization techniques shown in the preceding diagram.