210 Pa. Code r. 908
All parties to the matter in the court from whose order the appeal is being taken shall be deemed parties in the appellate court, unless the appellant shall notify the prothonotary of the appellate court of the belief of the appellant that one or more of the parties below have no interest in the outcome of the appeal. A copy of such notice shall be served on all parties to the matter in the lower court, and a party noted as no longer interested may remain a party in the appellate court by filing a notice that he has an interest in the appeal with the prothonotary of the appellate court. All parties in the appellate court other than the appellant shall be appellees, but appellees who support the position of the appellant shall meet the time schedule for filing papers which is provided in these rules for the appellant.
210 Pa. Code r. 908