Carry out maintenance to your CSD file.
You might occasionally (between CICS® releases) have to apply a service routine to carry out preventive or corrective maintenance to your CSD file. You do this by loading and running a special service program (DFHCUS1), which is supplied with CICS as a separately loadable module.
You can use the SERVICE command to create a new copy of the CSD file, from the existing CSD file. All the definitions are preserved, with the corrections (if any) applied.
This operand specifies the target service level to which the CSD file is to be upgraded, and must be 1 higher than the current level of FROMCSD. Specify it as a 3-character integer; for example, LEVEL(001).