As shown in the slide here, the improved versions of some of the P-channel MOSFETs at VDSS=-20V and low RDS(ON) measured at VGS=-1.5V. The TSM packaged SSM3J307T and SSM3J321T are the newer versions of the SSM3J13T with an RDS(ON) of 83mΩ and 137mΩ respectively.  Similarly, the SSM6J409TU is the newer version of the SSM6J51TU with an RDS(ON) of 150mΩ in a UF6 package.  Finally, the SSM3J130TU and SSM3J129TU are the newer versions of the SSM3J120TU with an RDS(ON) of 55.4mΩ and 137mΩ respectively in a UFM package.