Conversation so far:
why are there only 10 episodes of pretty little liars season 7
Pretty Little Liars season7 consisted of 20 episodes, in which ten episodes aired in the summer of 2016, with the remaining ten episodes aired from April 2017.
was there a season 8 of pretty little liars
On August 29, 2016, it was confirmed that season 7 would be the final season of the Pretty Little Liars series.

Question: why was the show cancelled
Self-contained rewrite: why was pretty little liars cancelled