Although this technical document refers to a specific fix, RO78180, the same procedure can be used to download any maintenance from CA Support Online that requires pre or co-requiste fixes.
Refer to the CA Support Online Compatibilities Matrix for information on the compatibility of the CA Mainframe Products and different Mainframe Environments.
You can also refer to Technical Document TEC1483297 which describes how to find the matrix itself. Although this document focuses on determining z/OS compatibility, it can be used to find the necessary maintenance needed for CA Mainframe Products and other OEM software such as z/OS, CICS, DB2, etc. as well as different hardware such as IBM's z12 and z13/z13s machines.