Do I need to recompile?

Ideally, programs should be compiled with a supported compiler (currently only IBM® Enterprise COBOL for z/OS® is supported) and run with a supported runtime library (Language Environment® for a supported version of z/OS). You can migrate programs gradually, in two stages:

• Stage 1: Runtime migration. See Chapter 3. Planning the move to Language Environment in the Enterprise COBOL 4.2 Compiler and Runtime Migration Guide for help in completing your runtime library migration.
• Stage 2: Compiler migration (you may compile only one or many programs in existing applications)