Today we published an update to 737 Immersion making it compatible with P3Dv4. In addition to P3Dv4 support, we fixed a long standing issue where the engine spray effects were assigned to the wrong engine. This update has been rolled out for FSX, FSX:SE and older versions of Prepar3D free of charge to existing customers. Prepar3D v4 users are not required to have Dynamic Lighting enabled to see volumetric lighting effects.
To update 737 Immersion, simply go in VFXCentral and press DIRECT INSTALL or MODIFY/UNINSTALL to enable the effects in P3Dv4.