Open that Plex app icon, scroll down to “other apps like this” and then near the bottom you should see “Plex Media Server”. Open that and you should see “Update”. This should update your server portion.

How do I manually update Plex?

To manually update your Plex library, log into the web control panel for your Plex Media Server. On the main page, select one of your libraries from the left hand navigation pane, as seen below, like your “TV Shows” library. Within the library, click on the circular arrow icon in the upper right corner.

How do I update Plex client?

On the settings, button in the page, under plex/web an orange button should be next to the version and you should be able to click that and it should just update.