According to The Athletic, multiple memebers of the 2018 Red Sox have told MLB that they used the replay room to steal signs that season.
Surely, replay rooms have been used for cheating since the moment they were created, which is something MLB tried to crack down on prior to the 2018 season by adding monitors. The Red Sox reportedly used zoomed-in video in the replay room to learn catcher's signals, which could then be relayed to batters when runners were on second base. They almost certainly weren't the only ones doing that through the years. Still, it's especially disturbing that it's another Alex Cora team getting busted, given that Cora was also with the 2017 Astros when they were cheating.
This is per rotoworld. Cora decided to take what he learned and apply it to the Sox. Wow, didn’t expect this