In what month and year was the release of the novel that "The Divergent Series: Allegiant" was based on?
The Divergent Series: Allegiant:  It is the first of two cinematic parts based on the novel "Allegiant", the final book in the "Divergent" trilogy by Veronica Roth, and the third installment in "The Divergent Series". Allegiant (novel): Allegiant is a science fiction novel for young adults, written by the American author Veronica Roth and published by HarperCollins in October 2013.
October 2013