long-running mirror task). This means that a transaction abend, unlike a CICS failure or a failure of the EXCI client, does not trigger an automatic rollback of the RRS UR. The EXCI options table DFHXCOPT has been amended recently to include the new option ABENDBKOUT={NO|YES}, which you can use to control transactional behavior following a CICS transaction abend. This option specifies whether a CICS transaction abend should trigger an automatic rollback of the RRS UR and backout all updates made by the long-running mirror. Tip: Specify ABENDBKOUT=YES in DFHXCOPT if you want to back out updates made by a long-running mirror following a transaction abend. This option is introduced as APAR PK17426 in CICS TS V3.1 and APAR PK17427 in CICS TS V2.2 and V2.3. 5.4 Transactional support in the CICS TG This section outlines the transactional support that is provided by the CICS TG for z/OS V6.1. CICS TG for z/OS operates as a long-running transactional EXCI client. In versions of CICS TG for z/OS prior to CICS TG V6.1, the Gateway daemon has a