CICS-supplied compatibility groups

If you share the CSD between CICS® Transaction Server for z/OS®, Version 5 Release 1 and an earlier release of CICS, you must ensure that the group list you specify on the GRPLIST system initialization parameter contains all the CICS-required standard definitions.

When you upgrade the CSD to the CICS TS for z/OS, Version 5.1 level, some IBM® groups that are referenced by your group list are deleted and the contents are transferred to one of the compatibility groups, DFHCOMPx. To ensure that these groups continue to be available to your CICS regions at earlier releases, add the compatibility groups after all the other CICS-supplied definitions.

For information about upgrading your CSD, and about the compatibility groups in CICS TS for z/OS, Version 5.1, see CSD compatibility between different CICS releases.