gdal - --optfile not working with gdal_retile?

I have the following gdal_retile command I am trying to run, but it errors on the --optfile:

gdal_retile.py -v -r bilinear -levels 8 -ps 512 512 -co "tiled=YES" -targetDir pyramid --optfile files.txt

   Unrecognised command option: -
   Usage: gdal_retile.py
        [-v] [-co NAME=VALUE]* [-of out_format]
        [-ps pixelWidth pixelHeight]
        [-ot  {Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/
               CInt16/CInt32/CFloat32/CFloat64}]

        [ -tileIndex tileIndexName [-tileIndexField fieldName]]
        [ -csv fileName [-csvDelim delimiter]]
        [-s_srs srs_def]  [-pyramidOnly] -levels numberoflevels
        [-r {near/bilinear/cubic/cubicspline/lanczos}]
        [-useDirForEachRow]
        -targetDir TileDirectory input_files

Any idea why this does not work?