Avoid rewriting or optimizing logic during the migration phase. Convert the project exactly as it is, verify it works on the new hardware, and optimize it later.
As of late 2021, Rockwell Automation has officially discontinued the Project Migrator as a standalone free download. The tool has been integrated or its functions replaced, so a simple, direct download is no longer an option. However, you still have a few reliable paths to access its functionality: rslogix project migrator tool download free