Please see this link:
This confirms that the CA Easytrieve product releases 6.4, 11.5, 11.6 are certified with the z15 processor and that there are no PTFs or additional maintenance required.
This information is actually for the family of CA Easytrieve products. Clicking on the product status for any release for the CA Easytrieve product, this is the link which will show each CA Easytrieve product for which has been certified with z15 successfully:
CA Pan/SQL 2.4C is therefore compatible with the z15 processor with no further maintenance required in order for the two to be compatible.