You can use the OS/VS COBOL MIGR compiler option whenever you are planning to convert an OS/VS COBOL program to Enterprise COBOL. This option helps you understand the magnitude of the conversion effort. It can also ease any planned future conversion by helping you avoid using OS/VS COBOL source language not supported by Enterprise COBOL. By compiling your programs using MIGR, you can determine ahead of time what language elements must be converted.
You can set the MIGR compiler option either as an installation default at install time, or when compiling an OS/VS COBOL program. When you set MIGR on, the compiler flags most statements that are changed in or not supported by Enterprise COBOL.