The latest episode of Arrow seems to have established that John "Digg" Diggle has not taken up the mantle of the Green Arrow. While earlier episodes had Digg denying that he had once again put on Oliver Queen's hood in a bid to protect Star City, there was still a chance that he was lying in order to conceal his vigilante activities; however, it now seems clear that Digg is not the new Green Arrow, following the events of "Crossing Lines."
The mysterious new Green Arrow first appeared in the season 7 premiere, "Inmate 4587". Every member of Team Arrow denied knowledge of who this new vigilante was. Rene Ramirez said that he had thought it was Digg, based on the fact that Oliver Queen had given Digg a new Green Arrow costume and asked John to take up his bow before going to prison. It was a logical guess, given that Digg had replaced Oliver as Green Arrow for the first half of season 6 when Oliver tried to retire from vigilantism.
Despite it being a logical outcome for Digg to become Green Arrow once more, Digg denied the possibility outright. This point was further developed in Arrow season 7, episode 2, 'The Longbow Hunters', which saw Digg having an argument with Felicity Smoak about his refusal to honor Oliver's wishes. Digg explained that he feared that putting on the hood again might lead to his family being torn apart the same way that Oliver's was. He also felt that he could do more good for Star City as an agent of the anti-terrorism group ARGUS than as Green Arrow.
While it seemed unlikely that Digg would lie to Felicity, it would not be the first time he's kept a secret from the rest of Team Arrow. At the same time, Digg was trying in earnest to fill Oliver Queen's hood in season 6, he was also secretly seeking treatment for a nervous condition that he developed following Arrow's fifth season finale. Given that, and the fact that we had no reports of the new Green Arrow in action while Digg was in the field on an ARGUS mission during the events of "The Longbow Hunters", many felt this might mean that Digg was honoring his promise to become the new Green Arrow in secret.
This seems less likely following episode 3 "Crossing Lines", which saw Digg traveling to Zurich with his wife (ARGUS Director Lyla Michaels) and Curtis Holt. Officially, they were there on a mission to retrieve the records of a bank that catered to various criminal enterprises. Unofficially, Lyla took advantage of Curtis' hacking to create a copy of the information for herself, so she could trade it to a Swiss criminal for information regarding a mole in ARGUS she could not fight through official channels. Digg discovered what Lyla was doing and admonished her, not for crossing a legal line, but for not consulting with him on an action that could have hurt their family if she'd been caught.
Given that "Crossing Lines" once again affirmed Digg's commitment to his family and that Lyla made mention of her understanding why Digg refused to become the new Green Arrow because of it, this would seem to definitively confirm that Digg is not the new Green Arrow. While Digg might lie to protect the ones he loves, it seems highly unlikely he would become a hypocrite on this point or go through this elaborate a scheme to protect his secret identity if he were the new Green Arrow. This still leaves viewers with the question - who is Arrow's new Green Arrow?
Season 7 of Arrow continues Monday, November 5 on The CW.