The Mule Migration Assistant (MMA) automates part of the migration of Mule 3 apps to Mule 4. Though the MMA does not migrate the app entirely, it provides significant help with these tasks:

• Migrating the project structure.
• Automatically creating descriptor files, such as pom.xml or mule-artifact.json.
• Automatically performing many adaptations of the app’s code.
• Providing guidance on how to manually migrate components and patterns that cannot be migrated automatically.

MMA helps with such tasks, but it does not deliver a fully functional app. Some additional steps are required. Those steps include testing and can also include:

• Manual migration of unsupported components.
• Manual migration of complex MEL expressions to DataWeave that cannot be automatically converted by MMA.
• Manual migration of complex DataWeave transformations that cannot be automatically converted by MMA.
• Prior migration of the DataMapper with the DataWeave Migration tool, before running the MMA.

It is also important to note that the MMA does not support incremental migrations.