If you have BTI updates specifying OPT=C as shown in the example below:
JOBCONN,USR
UPD,USR,TESTJOB1,USR=CHECK_PAYROLL_FILE,OPT=C,SCHID=0
The option 'C' is not documented. What is this option used for and why is it not documented?
OPT=C is an old option and has been replaced with OPT=A. If you have OPT=C coded in a BTI job, it will be treated as OPT=A (where option A is for add). This change was placed in CA 7 over 20 years ago and was documented at the time of the change.