Please ensure you have updated to Astute Manager v3 before proceeding. If the Astute Manager window is asking you to upgrade to version 3, you are still on version 2.
If you have previously installed the subscription plugins, you should see the Astute Manager menu bar icon (macOS) or Tray (Windows) indicate updates are available with a small red dot in the app icon as shown below:

Open the Astute Manager main window to discover what plugins have been updated:

Either install individual updates by clicking on the appropriate Update button, or click on the menu and select the Update All button.
Note that updates are only applied to the currently targeted version of Illustrator.
Forcing a check for updates
The Astute Manager periodically checks for updates, typically every few hours. If you want to force the Astute Manager to check for any updates immediately, enter the Updates section and click on the Check for plugin updates button as shown below:

For more details on managing your plugins, please refer to the Plugin management options in Astute Manager page.