Command "migrate-upgrade" is not defined

Local development environment on Windows 10 Pro: AMP stack is UniServerZ (PHP 7.1); Composer used to install Drupal 8.4.3 and Drush 9.x. Trying to upgrade Drupal 7 to Drupal 8. It's mostly a static website; nothing fancy. (And having solved, so far, various kinds of trouble that Drush throws up on Windows machines.)

All migrate modules are enabled. As far as I can tell, using the various "status" commands, Drush knows where to find the correct website.

Running "migrate-upgrade" both with and without pointing to an alias (and using the alias both before and after the command itself), get this error message (per the "configure-only" instructions on the relevant Drupal page):

[Symfony\Component\Console\Exception\CommandNotFoundException]
Command "migrate-upgrade" is not defined.

************************
I re-ran the command with the "verbose" tag, and got this result:

$ drush @[alias] migrate-upgrade --legacy-db-url=mysql://d7dev:[password]@127.0.0.1/d7dev                                --legacy-root=http://d7dev.example.com --configure-only -vvv
 [preflight] Config paths: C:\[path to Drupal Project]\vendor\drush\drush/drush.yml
 [preflight] Alias paths: C:\[path to Drupal Project]\drush\sites,C:\[path to Drupal Project]\web/drush/sites,
C:/[path to Drupal Project]/drush/sites
 [preflight] Commandfile paths: C:\[path to Drupal Project]\vendor\drush\drush\src
 [debug] Bootstrap further to find migrate-upgrade
 [debug] Trying to bootstrap as far as we can
 [bootstrap] Drush bootstrap phase: bootstrapDrupalRoot()
 [bootstrap] Change working directory to C:\[path to Drupal Project]/web
 [bootstrap] Initialized Drupal 8.4.3 root directory at C:\[path to Drupal Project]/web
 [bootstrap] Drush bootstrap phase: bootstrapDrupalSite()
 [bootstrap] Initialized Drupal site d8dev.example.com at sites/default
 [bootstrap] Drush bootstrap phase: bootstrapDrupalConfiguration()
 [debug] Add service modifier
 [info] sql-query: SELECT 1;
 [info] Executing: mysql --defaults-file="C:\\Users\\[user name]\\AppData\\Local\\Temp\\dru72AA.tmp" --database=d8dev --host=127.0.0.1 --port=3306 --silent  < "C:\\Users\\[user name]\\AppData\\Local\\Temp\\dru7299.tmp"
  1
 [info] sql-query: SELECT 1 FROM key_value LIMIT 1;
 [info] Executing: mysql --defaults-file="C:\\Users\\[user name]\\AppData\\Local\\Temp\\dru730A.tmp" --database=d8dev --host=127.0.0.1 --port=3306 --silent  < "C:\\Users\\[user name]\\AppData\\Local\\Temp\\dru72F9.tmp"
  1
 [bootstrap] Drush bootstrap phase: bootstrapDrupalDatabase()
 [bootstrap] Successfully connected to the Drupal database.
 [bootstrap] Drush bootstrap phase: bootstrapDrupalFull()
 [debug] Start bootstrap of the Drupal Kernel.
 [debug] Finished bootstrap of the Drupal Kernel.
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\config\ConfigCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\config\ConfigExportCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\config\ConfigImportCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\BatchCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\CliCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\DrupalCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\ImageCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\LocaleCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\QueueCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\RoleCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\StateCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\UserCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\ViewsCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\core\WatchdogCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\pm\PmCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\pm\ThemeCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\sql\SanitizeCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\sql\SanitizeCommentsCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\sql\SanitizeSessionsCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\sql\SanitizeUserFieldsCommands
 [debugnotify] Add a commandfile class: Drush\Drupal\Commands\sql\SanitizeUserTableCommands
 [debugnotify] Add a commandfile class: Drupal\migrate_tools\Commands\MigrateToolsCommands
 [debug] Done with bootstrap max in Application::find(): trying to find migrate-upgrade again.


  [Symfony\Component\Console\Exception\CommandNotFoundException]
  Command "migrate-upgrade" is not defined.


Exception trace:
 () at C:\[path to Drupal Project]\vendor\symfony\console\Application.php:562
 Symfony\Component\Console\Application->find() at C:\[path to Drupal Project]\vendor\drush\drush\src\Application.php:234
 Drush\Application->bootstrapAndFind() at C:\[path to Drupal Project]\vendor\drush\drush\src\Application.php:191
 Drush\Application->find() at C:\[path to Drupal Project]\vendor\symfony\console\Application.php:203
 Symfony\Component\Console\Application->doRun() at C:\[path to Drupal Project]\vendor\symfony\console\Application.php:125
 Symfony\Component\Console\Application->run() at C:\[path to Drupal Project]\vendor\drush\drush\src\Runtime\Runtime.php:111
 Drush\Runtime\Runtime->doRun() at C:\[path to Drupal Project]\vendor\drush\drush\src\Runtime\Runtime.php:41
 Drush\Runtime\Runtime->run() at C:\[path to Drupal Project]\vendor\drush\drush\drush.php:64