Although it is not listed in the Release Notes documentation, the compatibility test of Change Auditor 7.4 with the IT Security Search 11.6 has been conducted and it should be working as expected. No additional action is required besides the usual Data Source configuration:
https://support.quest.com/kb/4237359
In addition, this compatibility will be included as officially supported in the technical documentation in the next release of ITSS 11.6.1. It should still be safe to use 11.6, so upgrading to 11.6.1 only for this compatibility will be optional to the user once it reaches GA later in 2024.