A few features of the RPG III language are not supported in RPG IV. The most notable of these are:
Since the auto report function is not supported, the Conversion Aid will automatically expand these programs (that is, call auto report) prior to performing the conversion if the type is RPT or RPT38.
You must replace the FREE or DEBUG operation code with equivalent logic either before or after conversion.
If you specify the CVTRPT(*YES) option on the CVTRPGSRC command, you will receive a conversion report that identifies most of these types of problems.
For further information on converting auto report members, see Converting Auto Report Source Members. For further information on differences between RPG III and RPG IV, see Appendix A. Behavioral Differences Between OPM RPG/400 and ILE RPG for AS/400.