How Did King of the Hill End on Fox?

The end of Fox's King of the Hill happened twice - first on the network itself and then in syndication. Which episode was the intended series finale?

King of the Hill's Final Episode Embodies Everything Perfect About the Show

King of the Hill, FOX Wiki

King of the Hill Voices: Behind Favorite Characters

Why Fox's King of the Hill Ended (Was It Canceled?)

King of the Hill' might return to Fox

King of the Hill' Revival Ordered at Hulu

King of the Hill (season 13) - Wikipedia

King of the Hill Canceled By Fox - A+E Interactive

The Ending Of King Of The Hill Explained