When you start the server, it connects with the updates site in Internet and checks if there is a new version. If there is a new version then it shows a message with the version number and some headlines of the release notes.
The Phaser Editor Desktop distribution shows a message when there is a new update, but you should download the new version manually.
In v3 of the editor, you had the option of installing/updating Phaser Editor Core from NPM. Yet it is not available in Phaser Editor v4.