A new legal chapter opened this week in the tangled, long-running litigation between the Harbor View Hotel and a group of neighbors over an expansion project at the hotel, with the Massachusetts Appeals Court partly reversing a lower court decision that had dismissed a series of challenges involving the hotel’s controversial pool bar.

At issue in the case is both a technical challenge over mailed public hearing notices to abutters by the Edgartown zoning board of appeals, and a more pivotal question of whether the hotel has exceeded what was allowed in a special permit issued for the pool bar, originally dating to some two decades ago.

Both issues now return to the superior court for further review. The 16-page ruling was issued on Wednesday this week. Plaintiffs in the case are a group of nine neighbors led by Lynn Allegaert. Defendants are the Harbor View Hotel and the town of Edgartown, its building inspector and the zoning board of appeals.

The dispute has dragged on for nearly three years, with numerous bitter exchanges between the historic hotel and its longtime neighbors.

Residents of the surrounding Starbuck’s Neck neighborhood are unhappy about what they claim is creeping commercial expansion of a nonconforming use in a residential area, while hotel owners say they are simply acting within their legal rights to modernize the property overlooking the Edgartown Lighthouse.

Court documents partly reconstruct the complicated background in the case, which began as three cases and has seen numerous twists and turns.

In May 2019 the zoning board of appeals granted the hotel a special permit to relocate its pool bar on the premises.

When construction began a month later, the neighbors appealed in superior court, claiming that they had never received notice of a public hearing, and also that the special permit should not have been granted.

Because the appeal was filed after the 20-day statutory deadline, attorneys for the hotel moved to dismiss the case, and later prevailed.

In August 2019, the plaintiffs asked the town building inspector to enforce the zoning bylaws, claiming that the new pool bar was illegal because it went beyond the scope of the special permit.

The building inspector denied the request and the zoning board later upheld his decision. Neighbors appealed that decision in superior court.

In November 2019 and April 2020, all the claims were dismissed by different superior court judges. One judge concluded that the first appeal had been filed too late, and that the later enforcement appeal amounted to a back-door attempt to press the first appeal.

In the ruling this week, a three-judge panel on the state appeals court reached an opposite conclusion on two key issues: the timeliness of the original appeal and the validity of the request for enforcement by the building inspector.

The judges found that while an appeal on the merits of a special permit application was inarguably required within 20 days, a procedural challenge such as the one questioning whether proper notice had been mailed, would fall under a 90-day appeal period governed by a different statute.

“The plaintiffs raise numerous claims about the merits of the . . . special permit. These are time barred . . . The plaintiffs also raise claims about the town’s notification regarding the special permit. These claims are timely,” the judges wrote in part.

While remaining agnostic on the merits of the case, the ruling lightly raises an eyebrow at the fact that none of the abutters ever received notice of the public hearing.

“If true, the sheer number of persons who did not receive notice belies any suggestion that perhaps a notice was mislaid in the mail,” judges wrote.

As for the enforcement action complaint, the appeals court said that the superior court should not have dismissed the allegation concerning the size and scope of the pool bar without further review. Judges sent it back to the lower court to be heard again.

The court noted that the 2019 special permit “authorized only a 176-square-foot pool bar.” The plaintiffs allege that the new pool bar includes “a patio area of approximately 2,275 square feet with fire pits, approximately 60 lights, seating for approximately 50 patrons, and standing room for approximately 50 more . . . As the complaint alleges, this patio area was not included in the special permit.”

Attorneys on both sides of the protracted case claimed victory this week.

“The hotel is pleased that the appeals court upheld the trial court’s dismissal of the plaintiffs’ challenge to the 2019 special permit issued to the hotel for its pool bar and that the special permit remains in full force,” wrote Kevin O’Flaherty, a partner with Goulston & Storrs in Boston who represents the hotel, in an emailed statement to the Gazette.

“The hotel is confident that the limited issues the appeals court is remanding to the trial court for further proceedings will ultimately be resolved in favor of the hotel and the town,” he also wrote.

Felicia Ellsworth, a partner at WilmerHale in Boston who represents the neighbors, was similarly pleased.

“We are gratified by the appeals court’s decision . . . recognizing that residents are entitled to challenge both the issuance of the 2019 special permit without notice and the hotel’s unauthorized and unpermitted operation of an over-2,000-square-foot patio bar,” she said in an emailed statement to the Gazette.

“We will continue our efforts to hold the hotel accountable.”