Release notes for OpManager 12.5.604 (
https://www.manageengine.com/network-monitoring/help/read-me.html?servicePacks) are stating that SAML 2.0 capabilities have been introduced, and that there should be the "Authentication" section under "General Settings".
However, after updating to 12.5.604 we are not seeing these new features in our Settings (screenshot of "General Settings" section below, showing "User Management" only):