Piwik Upgrade - only "dry run" upgrading to 2.1.0

We’re having quite a large Piwik instance (~28 GB database) and we are currently test-upgrading from Piwik 1.12 to Piwik 2.1.0. After downloading and moving the new Piwik distribution to our web server (IIS), the Upgrade info page occured. So far so good.

As I’m told on the info page, I executed this code in the command line:

php C:\inetpub\wwwroot\piwik210/index.php -- "module=CoreUpdater"

However, I’m only getting dry runs (statements are printed to the command line and nothing else). After a lot of googling, I ended up searching the source code. I found this in plugins/CoreUpdater/Controller.php:

$doExecuteUpdates = Common::getRequestVar('updateCorePlugins', 0, 'integer') == 1;
if(is_null($doDryRun)) {
	$doDryRun = !$doExecuteUpdates;

Therefore, I executed this instead and it works:

php C:\inetpub\wwwroot\piwik210/index.php -- "module=CoreUpdater" -- updateCorePlugins=1

Am I missing something? How am I supposed to know that I have to run the command like this?

Any help appreciated!

The command has changed and now is: Update Piwik - Analytics Platform - Matomo