Plugins: can't get tutorial to work--Typerror

I’m trying this tutorial: https://gamedevacademy.org/create-a-dialog-modal-plugin-in-phaser-3-part-1/

I’m stuck on part 1. I copied all the code and set everything up as described, but I get the following error. I’ve checked everything 3x. What am I missing?

phaser.js:34533 Uncaught TypeError: this.plugins.installLocal is not a function
    at Systems.install (phaser.js:34533)
    at Scene.create (main.js:21)
    at SceneManager.create (phaser.js:76987)
    at SceneManager.loadComplete (phaser.js:76899)
    at LoaderPlugin.emit (phaser.js:1732)
    at LoaderPlugin.loadComplete (phaser.js:172397)
    at LoaderPlugin.fileProcessComplete (phaser.js:172363)
    at PluginFile.onProcessComplete (phaser.js:4242)
    at PluginFile.onProcess (phaser.js:169285)
    at LoaderPlugin.nextFile (phaser.js:172297)

I think the plugin API from that tutorial is obsolete.