We have not tried COBOL 5.2 with R17, but we did do some testing with R16. The biggest thing to be aware of is the expanded number of work files needed by COBOL 5.2 and the storage requirements. Best guess is that it takes close to 300 Meg to compile a program. As we do a high percentage of compiles in TSO foreground, you need to be aware that the user's TSO profile must allow for that much storage. For other reasons, we backed away from COBOL 5.2 temporarily, but it is in our plan to implement in the near future.