Based on https://docs.wildfly.org/27/wildscribe/subsystem/iiop-openjdk/index.html#attr-security the `identity` is still possible value to write to `security` attribute of `iiop-openjdk`subsystem.
But when I try to write it, the operation fails with:

{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0158: Operation handler failed: java.lang.I
llegalStateException: WFLYCTL0365: Capability 'org.wildfly.legacy-security' is u
nknown in context 'global'.",
    "rolled-back" => true
}

This scenario works fine with EAP 7.4.10

It's possible that this is not a bug. As this is not very well documented, could someone who has more knowledge on this matter provide some more information?