Clicking «hide tour» on any of these popups will turn them off - you can enable again, if you're in the mood, from the «Help» - > «Welcome Tour» menubar option. (elearningindustry.com)
By default the Plex Media Server does not appear as an item in your Dock on OS X. (It will always appear in the top menubar.) (support.plex.tv)
Thanks to the notch eating up a big chunk out of the top of the iPhone X screen, there's not as much space up there for useful menubar widgets. (cultofmac.com)