Plaintiffs suing over a 2014 data breach at the U.S. Office of Personnel Management—which may have compromised information for 21.5 million persons—have asked a federal appeals court to revive their cases, citing a significant decision last year finding standing to sue over a cyberattack.

Plaintiffs filed opening briefs before the U.S. Court of Appeals for the District of Columbia Circuit on Thursday in two cases—one on behalf of a class of victims of the data breach and the other by a government employees union. They asked the panel to reverse a district judge’s Sept. 19, 2017, opinion that dismissed their cases, in large part on the ground that the plaintiffs didn’t have standing to sue in federal courts because they hadn’t been injured. In so ruling, U.S. District Judge Amy Berman Jackson of the District of Columbia “wrongly sidestepped” the D.C. Circuit’s Aug. 1, 2017, decision in Attias v. CareFirst , a data breach case that called for a broader view of standing.