Supported upgrade paths to 11.1.2.4
From 11.1.2.x:
In general, you can apply the maintenance release to upgrade to 11.1.2.4. However, If you are on HFM 11.1.2.1, you must upgrade to at least 11.1.2.1, .2, or .3 first. If you are using FCM, the maintenance release is only supported from version 11.1.2.2 and 11.1.2.3.
From 11.1.1.4.x:
Upgrade to 11.1.2.3 first, then upgrade to 11.1.2.4
From 11.1.1.0.x to 11.1.1.3.x:
Apply maintenance release to 11.1.1.4, then upgrade to 11.1.2.3, then upgrade to 11.1.2.4