OPINION *

Harold and Maria DeJesus appeal the District Court’s order, which granted (i) Knight Industries & Associates, Inc.’s motion to preclude expert testimony, and (ii) Knight’s motion for summary judgment on negligence and strict liability claims arising from an alleged defectively designed lift table.

In opposing summary judgment, DeJe-sus argued that the Restatement (Second) of Torts was the substantive law that applied to his product liability claims. 1 The District Court applied the Restatement (Third) of Torts, consistent with this Court’s decision in Covell v. Bell Sports, *455 Inc., 2 holding that district courts must apply the Restatement (Third) to design defect claims arising under Pennsylvania law, absent a controlling contrary holding from the Pennsylvania Supreme Court. After the grant of summary judgment for Knight and while the case was pending on appeal, the Supreme Court of Pennsylvania decided Tincher v. Omega Flex, Inc. and held that “Pennsylvania remains a Second Restatement jurisdiction.” 3 At the same time, the Court overruled the longstanding method of applying the Restatement (Second) outlined in Azzarello v. Black Brothers, 4

DeJesus properly preserved his rights with respect to the issue resolved by Tincher. He moved for a stay of the appeal pending the resolution of Tincher, which we denied. 5 He also reserved his right to brief the issue of applicability of Tincher to his claims in his appellate brief. 6

Because the law as decided by the highest court of the state has changed while the case was on appeal, and because DeJe-sus preserved his rights with respect to the issues that have since been resolved in Tincher, we will vacate the District Court’s grant of summary judgment and remand the case for further proceedings in light of Tincher. 7 As to the issue of admissibility of the testimony of Dejesus’s expert witness, whether that witness be Dr. Rider or another expert, we will leave the resolution of that question to the District Court to be determined at the time that expert witness testimony is offered by DeJesus.