Identity Manager 3.5 and 3.5.1 contain a new policy architecture, which affects how drivers reference policies. While the 3.5.1 driver architecture offers increased functionality in the Identity Manager 3.5.1 environment, the 3.0.x Metadirectory engine cannot run 3.5.1 driver configurations.
However, Identity Manager 3.5 and 3.5.1 can run 3.0x driver configurations. If you have 3.0.x driver configurations associated with both 3.0.x and 3.5.1 Metadirectory engines, do not upgrade the 3.0.x drivers. The 3.0.x driver configurations work in a 3.5.1 environment, but they don’t have the increased functionality that Identity Manager 3.5 and above affords. When 3.0.x driver configurations are only associated with a 3.5 or later Metadirectory engine, you should then upgrade the 3.0.x drivers to 3.5.1.
For more information on policy architecture and upgrading drivers to 3.5.1, see Upgrading Identity Manager Policies
in Understanding Policies for Identity Manager 3.5.1.