Complex sentence: In late 2011, BOOM! also began publishing the 4-issue miniseries "Betrayal of the Planet of the Apes"; a series set 20 years before the events of the original film, and not part of the continuity of the concurrent ongoing series.
Split into simpler sentences: In late 2011, BOOM! also began publishing the 4-issue miniseries "Betrayal of the Planet of the Apes". This miniseries is set 20 years before the events of the original film, and is not part of the continuity of the concurrent ongoing series.