However, in 2017, a fifth and final season of Prison Break was released, which consisted of nine episodes. The final season concluded on June 27, 2017.

So, to answer your question, Prison Break initially ended on May 27, 2009, but the series was revived for a final season that concluded on June 27, 2017.

To provide a definitive conclusion to Season 4, a standalone feature titled The Final Break was released on DVD and Blu-ray on July 21, 2009 . It chronologically took place before the "four years later" flash-forward seen in the Season 4 finale.