After upgrading to a new release, clients may see CICS tasks end with a S006 abend for any transaction.
This can be caused by an inadvertent change in the #UCFCICS macro parameters.
Release : 19.0 or any supported release
Component : IDMS UCF
If all parameters in #UCFCICS remain the same in an upgrade, no problems should occur. However, sometimes in an upgrade things are overlooked and one or more of these parameters get changed unintentionally.
In particular, if a site has EXIT27 in place that will change the CICS USERID, then the CV must run with the UCFCICS parm USERCHK=NO. If this is somehow changed to USERCHK=YES in the course of an upgrade, then the S006 can occur. This is because running with USERCHK=YES is incompatible with using an EXIT27 to change CICS Userids; these cannot both be implemented at the same time in the same environment.
If it is necessary to run with USERCHK=YES for some reason, and EXIT27 was previously in place, another option may be to use the USERIDXIT instead of the EXIT27.Here's what the doc for USERCHK=YES says:
"The comparison of the new and saved userid is done after the call to the USRIDXIT, if that exit exists. The value set by the USRIDXIT is the one that is saved across a pseudo-converse, so the use of the exit with USERCKHK=YES should not cause a problem even if the exit modifies the user ID used to connect to the back-end DC/UCF system. "