Determining the callable service release level

New callable services may be added with each new z/OS UNIX release. Depending on the operating environment, the caller may have to determine the release level of z/OS UNIX before a new callable service can be issued.

The release information is indicated in the CVT feature flags. For z/OS® V1R1, the feature flag is:

CVTJ7713 EQU   X'20'         JBB7713