QML Runtime Tool help all option is not working

D:\QtQSR2.0\5.15.7\mingw81_64>D:\QtQSR2.0\5.15.6\mingw81_64\bin\qml.exe --help
Usage: D:\QtQSR2.0\5.15.6\mingw81_64\bin\qml.exe [options] [files...] [-- args...]Options:
  -?, -h, --help                   Displays help on commandline options.
  --help-all                       Displays help including Qt specific options.
  -v, --version                    Displays version information.
  -a, --apptype <core|gui|widget>  Select which application class to use.
                                   Default is gui.
  -I <path>                        Prepend the given path to the import paths.
  -f <file>                        Load the given file as a QML file.
  -c, --config <file>              Load the given built-in configuration or
                                   configuration file.
  --list-conf                      List the built-in configurations.
  --translation <file>             Load the given file as the translations
                                   file.
  --dummy-data <file>              Load QML files from the given directory as
                                   context properties.
  --desktop                        Force use of desktop OpenGL
                                   (AA_UseDesktopOpenGL).
  --gles                           Force use of GLES (AA_UseOpenGLES).
  --software                       Force use of software rendering
                                   (AA_UseSoftwareOpenGL).
  --scaling                        Enable High DPI scaling
                                   (AA_EnableHighDpiScaling).
  --no-scaling                     Disable High DPI scaling
                                   (AA_DisableHighDpiScaling).
  --quiet                          Suppress all output.
  --verbose                        Print information about what qml is doing,
                                   like specific file URLs being loaded.
  --slow-animations                Run all animations in slow motion.
  --fixed-animations               Run animations off animation tick rather
                                   than wall time.
  -r, --rhi <backend>              Use the Qt graphics abstraction (RHI)
                                   instead of OpenGL directly. Backend is one
                                   of: default, vulkan, metal, d3d11, gl
  -S <selector>                    Add selector to the list of
                                   QQmlFileSelectors.Arguments:
  files                            Any number of QML files can be loaded. They
                                   will share the same engine.
  args                             Arguments after '--' are ignored, but passed
                                   through to the application.arguments variable
                                   in QML.D:\QtQSR2.0\5.15.7\mingw81_64>D:\QtQSR2.0\5.15.6\mingw81_64\bin\qml.exe --help-all
qml: No files specified. Terminating.