Moved to HIPs where someone should be able to help you soon.
The latest extension 18.104.22.1688 should be backwards compatible and cover anything the previous extensions had covered. I am not sure that they keep old extensions available for downloads. If you login with your Grant number you may want to check under previous HIPS 8 patches.
List of HIPS 8 and HIPS 8 extension version numbers McAfee KnowledgeBase - Host Intrusion Prevention 8.0 patch and hotfix version information
The article on the specific extension you had requested https://kc.mcafee.com/corporate/index?page=content&id=KB78573 The readme notes(McAfee KnowledgeBase - Host Intrusion Prevention 22.214.171.1242 Extension Release Notes) did not indicate a specific download location.
The problem is that the upgrade of the extension in the epo causes that the epo crashes so i had to unistall the version 126.96.36.1998 manually and i want to install the old version that i know it works fine until i can know what causes the problem but in the mcafee downloads section is not longer available.