Never hurts to read the article first: "It’s small and unobtrusive, and no matter what you do with it (click any button, close it, etc) it’ll go away until next year. It’s implemented as a KDE Daemon (KDED) module, which allows users and distributors to permanently disable it if they like. You can also disable just the popup on System Settings’ Notifications page, accessible from the configure button in the notification’s header."