Look in the lower right corner of the launcher window. The current version of the game is 5.0.8.2623en. If that's showing in the window, go ahead and close the launcher (there's a close box in the extreme upper right of the window), then restart it.
Even if the version number doesn't match the current version, it's usually safe to close and restart the launcher. If it isn't completely up-to-date, it will begin the patching process again.