If set to "true", configures DIFxApp to install unsigned driver packages and driver packages with missing files. For more information, see "Installing Unsigned Driver Packages in Legacy Mode" earlier in this paper. If this attribute is set to "false" or not present, DIFxApp will install only signed driver packages. Note that configuring DIFxApp to install unsigned drivers is controlled by the Flags entry value of the component that represents the driver package in the MsiDriverPackages custom table. Setting Legacy to "true" sets the corresponding bit in the Flags entry value. Setting Legacy to "false" clears the bit in the Flags entry value that configures DIFxApp to install unsigned driver packages. If this attribute is not present, DIFxApp uses a default value of "false".