You can upgrade from any 3.x version of the Active Directory driver. Upgrading a pre-3.x version of the driver directly to version 4.0.2.1 is not supported.
NOTE:If you upgrade to version 4.0.2.1 of the Active Directory driver, you need the Identity Manager 4.6-based Product Activation Credential to use the upgraded driver. The activation level has been increased due to the addition of an additional feature.