Jennifer Maas TV Business WriterMatt and Ross Duffer, aka the Duffer Brothers, decided to break up their nine-episode fourth season of “Stranger Things” in a rather unconventional way. By now, most fans of the Upside Down surely know that the first portion of the season, which launches Friday, consists of seven super-sized episodes, while Volume 2, which debuts July 1, has only two installments.Though Episodes 8 and 9 are longer than all the episodes that came before them, running at 85 minutes and nearly two and a half hours, respectively, there could still be concerns among viewers that only two episodes does not a second volume make.But the Duffers assured Variety that Episode 7 of “Stranger Things 4” is not just at the level of any previous season closer they have done, but sets up Episodes 8 and 9 in a way that makes the two-episode Volume 2 feel like it can stand alone.