Litigation summary

Litigation History of U.S. Patent No. 8,942,252B2

U.S. Patent No. 8,942,252B2, titled "Method and system synchronization of content rendering," has been the subject of multiple legal challenges, including district court litigation, an Inter Partes Review (IPR) at the Patent Trial and Appeal Board (PTAB), and subsequent appeals to the U.S. Court of Appeals for the Federal Circuit and the U.S. Supreme Court. The primary litigants identified are the patent owner, Implicit, LLC, and the audio electronics company, Sonos, Inc.

District Court Litigation

At least two district court cases have been identified involving a patent from the same family as US8942252B2, asserted by Implicit, LLC.

1. Implicit, LLC v. Sonos, Inc.

• Plaintiff: Implicit, LLC
• Defendant: Sonos, Inc.
• Jurisdiction: U.S. District Court for the District of Delaware
• Case Number: 1:17-cv-00259-LPS.
• Filing Date: March 10, 2017.
• Status/Outcome: This case was the precursor to the Inter Partes Review filed by Sonos. The district court proceedings were likely stayed pending the outcome of the IPR. The ultimate invalidation of the patent claims in the IPR and subsequent affirmation on appeal would render the infringement claims in this case moot.

2. Implicit, LLC v. D&M Holdings U.S. Inc.

• Plaintiff: Implicit, LLC
• Defendant: D&M Holdings U.S. Inc.
• Jurisdiction: U.S. District Court for the District of Delaware
• Case Number: 1:17-cv-00258-LPS.
• Filing Date: March 2017.
• Status/Outcome: This case appears to have been filed concurrently with the Sonos litigation and is related to the same patent family. The outcome was likely impacted by the IPR decision against the asserted patents.

No specific litigation dockets have been found for complaints filed by Implicit, LLC against Apple Inc. or Samsung Electronics Co. Ltd. concerning patent US8942252B2.

Inter Partes Review (IPR)

An IPR was filed by Sonos, Inc. challenging the validity of the claims of US8942252B2 and a related patent.

• Petitioner: Sonos, Inc.
• Patent Owner: Implicit, LLC
• Jurisdiction: U.S. Patent and Trademark Office, Patent Trial and Appeal Board (PTAB)
• Case Number: IPR2018-00767
• Filing Date: The petition was accorded a filing date of October 16, 2017.
• Outcome: In a final written decision issued in September 2019, the PTAB found the challenged claims of US8942252B2 to be unpatentable. The Board determined that Implicit's evidence was insufficient to predate a prior art reference.

Federal Circuit Appeal

Implicit, LLC appealed the PTAB's decision to the U.S. Court of Appeals for the Federal Circuit.

• Appellant: Implicit, LLC
• Appellee: Sonos, Inc.
• Jurisdiction: U.S. Court of Appeals for the Federal Circuit
• Case Numbers: 20-1173, 20-1174
• Filing Date: The appeal was decided on March 9, 2026.
• Outcome: The Federal Circuit affirmed the PTAB's decision, upholding the invalidity of the challenged claims of US8942252B2. The court found that Implicit had forfeited its new arguments regarding inventorship by not raising them earlier in the proceedings.

U.S. Supreme Court Petition

Following the Federal Circuit's decision, Sonos, Inc. filed a petition for a writ of certiorari to the U.S. Supreme Court.

• Petitioner: Sonos, Inc.
• Respondent: Implicit, LLC
• Jurisdiction: U.S. Supreme Court
• Case Number: 20-1654
• Filing Date: The petition was docketed on May 26, 2021.
• Outcome: The petition was denied on October 18, 2021.