You can run existing load modules under Language Environment and receive the same results as with pre-Language Environment libraries. For important compatibility information, see Running existing applications under Language Environment.
For information on moving applications that are running under older PL/I run-times, see Considerations Before Migrating.
In almost all cases, you will need to link-edit existing applications with Language Environment or recompile programs with Enterprise PL/I. To determine which programs require link-editing with Language Environment, see Link-Edit Considerations.