Warning: The following contains SPOILERS for Stargirl Spring Break Special #1.
DC Comics has finally addressed a long-running plot hole regarding Green Arrow and the Seven Soldiers of Victory. Green Arrow was originally a founding member of the team, but this became impossible as the history of DC Comics' cosmology changed over the years. This resulted in several stories that conflicted with the established continuity and a lot of confusion regarding the group.
Originally, there were two versions of Green Arrow: one who lived on Earth-1 and was part of the Justice League of America and another who lived on Earth-2 and was part of the Seven Soldiers of Victory. The Green Arrow of Earth-2 died during Crisis on Infinite Earths, which condensed all the surviving Earths into a single world. In the new Earth's history, most of the heroes of Earth-2 fought crime during World War II and Oliver Queen did not become Green Arrow until the modern day and was never a part of the Seven Soldiers of Victory. Despite this, a number of stories continued to depict Green Arrow and his sidekick Speedy as part of the team, even after Geoff Johns wrote a new history for the Seven Soldiers of Victory which established a new line-up that didn't include Oliver Queen and Roy Harper.
Johns recently stepped in again to finally explain the plot hole with a story in Stargirl Spring Break Special #1, which establishes a new history for the reality of Infinite Frontier. The story shows Emiko Queen, the current Red Arrow and Oliver Queen's half-sister, trying to take the wind out of his sails as he is lecturing her on proper archery technique, by pointing out that he wasn't the first Green Arrow and has ripped off his name and gimmick from some hero from World War II. To her surprise, Oliver insists that he hasn't stolen anything and that he is also the Green Arrow of the Golden Age of Heroes.
Oliver explains that early in his career he and his first sidekick, Roy Harper, had gotten into a fight with the villain Clock King, who was obsessed with time-pieces and time-travel. One of Clock King's prototype time machines exploded while Green Arrow and Speedy were next to it and the resulting energy wave sent them back in time. They lived there for several years, keeping their Green Arrow and Speedy identities, but adopting costumes more appropriate to the times, eventually meeting other heroes and founding the Seven Soldiers of Victory. They were eventually restored to their proper place in time, ironically after a battle with the cosmic villain Nebula Man sent all of the Seven Soldiers who survived into the modern day.
Beyond correcting a major plot hole and restoring the legacy of one of DC Comics' first superhero teams for the modern age, Johns' story also explains how heroes like Stripesy and Vigilante and the rest of the Seven Soldiers of Victory are still active in the present in the reality of Infinite Frontier. It also cements the prominent position Green Arrow holds as a piece of DC Comics history, just in time for his 80th anniversary. Now Oliver Queen and Roy Harper stand unique as the only two heroes who have defended Earth-Prime across two time periods.