The CA GEN Z/OS Support Matrix LINK
shows additional Info:
CA GEN 8.5 code compiled to execute in z/Architecture mode, ARCH(5)
What does this ARCH Level mean?
ARCH levels are IBM terms. The "additional Info" means that also tests was done for IBM specific ARCHLEVELs.
If you are running with any of this listed arch(5) level or arch(6), this was tested with CA GEN 8.5 and support details are described
in the LINK you referred to. Please contact you System ADMIN or IBM if you don't know on which ARCH Level your z/OS is running.
Details related Arch level can be found on:
Specifically, ARCH(5) is the minimum requirement for execution of a program in 64-bit mode. If you explicitly set ARCH to a lower level,
the compiler will issue a warning message and ignore your setting. ARCH(5) specifies the target machine architecture and the
application can be either 31-bit or 64-bit.
Specifically, these ARCH(6) machines and their follow-ons add the long-displacement facility. For further information on the long-displacement facility, refer to z/Architecture Principles of Operation.