What is the preferred way of updating Yeoman generators?

If you want to update a specific generator you can run npm update generator-mygenerator -g

Nice if you have many generators installed.

Glad you asked!

Starting with Yeoman RC1, which will be announced later today, there's a brand new way to manage your generators: Just enter yo and enjoy the new wizard:

If you select "Update Generators" from the menu, yo yo will take care of bringing them all to the latest version.

If you are a generator author and want to go one step further to make sure your users are always up-to-date, you can use update-notifier from the Yeoman project to greet users with a notification if they run an obsolete version.