Hi Dev,
Please refer the below documents and blog
Generate a Migration Report from PI Dual-Stack to AEX
Moving Integration Directory Artifacts from dual stack to single stack
As a pre migration activity
1. Identify the no of interface and there types
2. Identify if any CCBPM and then plan the creation of new NWBPM for CcBPM
3. Identify what type of adapters are used and plan the ABAP stack adapter movement to Java stack adapter like IDOC to IDOC_AAE, HTTP to HTTP_AAE, XI to SOAP over XI etc.
4. Identify any B2B sceanrio and check if you are using any third party adapter
5. Identify the ABAP mapping or any other abap object and create them to Java mapping (java objects).
regards,
Harish