PTAB challenges

Proceedings overview

US Patent 11539663 is currently subject to two active Inter Partes Review (IPR) proceedings. Both proceedings, IPR2026-00183 and IPR2026-00362, are in the early, pending stages, meaning no institution decisions or final written decisions have been issued. This indicates that the patent's claims remain active and have not yet been substantively reviewed by the Patent Trial and Appeal Board (PTAB). For a defendant, this means the patent's claims are currently active and unhardened by PTAB review.

IPR2026-00183 — Microsoft Corporation v. QOMPLX LLC

• Type: Inter Partes Review
• Filed: 2026-01-14
• Status: Pending. The petition has been filed and is currently awaiting the Patent Owner's preliminary response and the PTAB's institution decision.
• Judge panel: Not yet public.
• Petition grounds: Not yet public. These grounds will specify which claims are challenged, the prior art asserted, and the statutory basis (e.g., § 102 for anticipation, § 103 for obviousness).
• Institution decision: Not yet issued. The statutory deadline for the PTAB to decide whether to institute an IPR is typically six months from the filing of the petition.
• Final Written Decision: Not yet issued.
• Settlement / termination: Not yet occurred.
• Appeal: Not applicable at this stage.
• Defensive value: The claims of US11539663 are currently active and valid. This proceeding represents an early challenge to the patent's validity, but no determination has been made by the PTAB.

IPR2026-00362 — Palo Alto Networks, Inc. v. QOMPLX LLC

• Type: Inter Partes Review
• Filed: 2026-05-15
• Status: Pending. The petition has been filed and is currently awaiting the Patent Owner's preliminary response and the PTAB's institution decision.
• Judge panel: Not yet public.
• Petition grounds: Not yet public.
• Institution decision: Not yet issued. The statutory deadline for the PTAB to decide whether to institute an IPR is typically six months from the filing of the petition.
• Final Written Decision: Not yet issued.
• Settlement / termination: Not yet occurred.
• Appeal: Not applicable at this stage.
• Defensive value: The claims of US11539663 are currently active and valid. This proceeding, like IPR2026-00183, is an early challenge, and the PTAB has not yet ruled on the merits of the petition.

Strategic summary

Currently, all claims of US Patent 11539663 remain UNTESTED and ACTIVE because neither of the two IPR proceedings (IPR2026-00183 and IPR2026-00362) has reached the institution decision phase, let alone a Final Written Decision. Therefore, the patent has not yet been narrowed or hardened through PTAB review.

Regarding the estoppel landscape, since no Final Written Decisions have been issued, the estoppel provisions of 35 U.S.C. § 315(e)(2) do not yet apply. This means that both petitioners (Microsoft Corporation and Palo Alto Networks, Inc.) and their privies would not yet be barred from raising any ground they raised or reasonably could have raised in the IPRs. For a defendant currently facing assertion of this patent, all prior-art grounds remain potentially available for challenge, either through future IPRs or in district court litigation, assuming no other prior art or procedural bars apply.

The pattern of two separate IPR filings by distinct, prominent technology companies (Microsoft and Palo Alto Networks) within a few months of each other signals that US11539663 is attracting attention from entities potentially impacted by its claims. This could indicate the patent is being asserted in the market or is perceived as a significant intellectual property asset. The fact that Unified Patents listed IPR2026-00183 on its portal suggests it's a patent of interest, though Unified Patents is not the petitioner in this instance.

Recommended next steps

Since both IPR2026-00183 and IPR2026-00362 are pending, the immediate next key milestones to monitor are the institution decision deadlines.

• For IPR2026-00183 (filed 2026-01-14), the PTAB's institution decision is typically due approximately 2026-07-14.
• For IPR2026-00362 (filed 2026-05-15), the PTAB's institution decision is typically due approximately 2026-11-15.

These decisions will reveal which, if any, claims are deemed to have a reasonable likelihood of being found unpatentable and will proceed to trial. Until these decisions are rendered, all claims of US11539663 are presumed valid. For further details on IPR2026-00183, refer to the Unified Patents PTAB Data portal: https://portal.unifiedpatents.com/ptab/case/IPR2026-00183

The full text of the patent US11539663B2 can be found here: https://patents.google.com/patent/US11539663/en