Enterprise COBOL Version 4 introduces new XML PARSE support compared to Enterprise COBOL Version 3. In particular, the z/OS System Services XML parser is now supported as an alternative to the XML parser that is part of the COBOL runtime library.
Enterprise COBOL Version 4 introduces a new compiler option, XMLPARSE, to control which parser is used for XML PARSE statements:
You do not have to change your Enterprise COBOL Version 3 programs that use XML PARSE statements to upgrade to Enterprise COBOL Version 4, you can just specify the compiler option XMLPARSE(COMPAT).
The compiler default is XMLPARSE(XMLSS), so if you want to have compatible behavior you need to specify XMLPARSE(COMPAT).
You may have to change your Enterprise COBOL Version 3 programs that use XML PARSE statements if you want to change to use XMLPARSE(XMLSS).
To migrate your Enterprise COBOL Version 3 programs to use XMLPARSE(XMLSS), change the programs to reflect the new, changed, and discontinued XML parsing events that you get when XMLPARSE(XMLSS) is in effect.