Arc Link LLC filed a complaint for patent infringement against Sophos Limited on June 18, 2026, in the U.S. District Court for the Eastern District of Texas, Marshall Division. The docket lists the case as No. 2:26-cv-00490, assigned to U.S. District Judge Robert W. Schroeder III, with the cause recorded as "28:1338 Patent Infringement" and a jury trial demanded by the plaintiff. The complaint and a civil cover sheet were filed as docket entry 1; the filing was made by counsel John Rubino of Rubino IP. The case is sourced here from the free RECAP/PACER docket mirror, which carries the 29-page complaint.

Per the complaint, Arc Link describes itself as a Texas limited liability company with its principal place of business in Marshall, Texas. It pleads that Sophos is a corporation organized under the laws of the United Kingdom, headquartered at the Pentagon, Abingdon Science Park, Oxfordshire, and that Sophos may be served under the Hague Convention. Arc Link asserts venue in the district under 28 U.S.C. § 1391(c)(3) on the basis that Sophos is not a U.S. resident and so, it argues, may be sued in any judicial district.

The four patents-in-suit

The complaint asserts four U.S. patents, which it collectively calls the "Patents-in-Suit." According to the filing, they are:

  • U.S. Patent No. 9,549,328, "Method to Optimize the Communication Parameters Between an Access Point and at Least One Client Device," which the complaint says issued January 17, 2017, and names inventors Julien Herzen, Ruben Merz, and Patrick Thiran.
  • U.S. Patent No. 11,563,655, "Network Monitoring Apparatus and Method Thereof in Programmable Network Virtualization," stated to have issued January 24, 2023, with inventors Gyeongsik Yang, Minkoo Kang, and Hyuck Yoo.
  • U.S. Patent No. 8,200,592, "System and Method for Modeling Multilabel Classification and Ranking," stated to have issued June 12, 2012, with inventors Klaus Brinker and Claus Neubauer.
  • U.S. Patent No. 9,552,548, "Using Classified Text and Deep Learning Algorithms to Identify Risk and Provide Early Warning," stated to have issued January 24, 2017.

The complaint states that Arc Link "is the sole and exclusive owner of all right, title, and interest" in the four patents and asserts the right to enforce them and to recover damages for past, present, and future infringement.

The accused Sophos products, count by count

Each patent is asserted in its own count, and the complaint identifies an exemplary accused product for each while reserving a broader list. The pleading frames the overall infringement allegation in general terms:

Sophos has infringed and continues to infringe the Patents-in-Suit by making, using, selling, offering to sell, and/or importing, and by actively inducing others to make, use, sell, offer to sell, and/or importing, products that infringe the Patents-in-Suit.

Count I (the ’328 patent) targets Sophos wireless gear. The complaint accuses "at least claim 1" and identifies, among others, the Sophos AP6 Series access points (including the AP6 420, 420E, 420X, 840, and 840E), the Sophos APX Series (including APX 120, 320, 320X, 530, and 740), Sophos Central Wireless, Sophos Wireless, and related access-point and cloud-management software. The complaint uses the Sophos AP6 840E access point, operated with Sophos Central wireless-management software, as its exemplary product.

Count II (the ’655 patent) concerns virtualized-network monitoring. It accuses "at least claim 1" and names Sophos Firewall v21.0, v21.5, and later releases configured as virtual, cloud, or software appliances — including the Sophos Firewall Virtual Appliance for VMware ESXi, KVM, Citrix Hypervisor, and Nutanix Prism — plus Sophos Central firewall management and the Sophos Firewall Manager. The exemplary product is the Sophos Firewall v21.5 Virtual Appliance for VMware ESXi, which the complaint maps to a "network hypervisor implementing software-defined-network-based network virtualization."

Count III (the ’592 patent) reaches Sophos's detection and response stack. It accuses "at least claim 20" and lists Sophos Central XDR, Sophos XDR, Intercept X Advanced with XDR, Intercept X Advanced for Server with XDR, the Sophos Data Lake, the Sophos Threat Analysis Center, Sophos MDR, Sophos NDR, and related monitoring, detection, and reporting software. Sophos Central XDR, operated with Sophos Endpoint, Server, Firewall, Email, and other feeds, is the exemplary product.

Count IV (the ’548 patent) targets email security. It accuses "at least claim 17" and names Sophos Email, Sophos Email Security, Email Advanced, Email Plus, Sophos Mailflow, Sophos Gateway, plus SophosLabs, SophosAI, the Sophos AI Assistant, and related email-security and threat-intelligence products. Sophos Email Security is the exemplary product, with the count tying it to a method of "using classified text and deep learning algorithms to identify risk and provide early warning."

Across the counts, the complaint pleads direct infringement under 35 U.S.C. § 271(a) as well as indirect infringement — inducement under § 271(b) and contributory infringement under § 271(c) — and alleges knowledge and willful blindness on Sophos's part. It pleads compliance with the marking requirements of 35 U.S.C. § 287. In its prayer for relief, Arc Link asks the court to enter judgment that Sophos infringed, to award damages, and to declare the case exceptional.

What the docket establishes

At this stage the record reflects a newly filed complaint and an initial summons request — not any response from Sophos, which had not yet appeared or answered as of the docket pulled here. The allegations described above are the plaintiff's, drawn from the complaint; nothing in the docket adjudicates them. As is standard for a patent case filed against a foreign defendant in this district, service under the Hague Convention and any venue or jurisdictional challenges remain ahead. We will follow the docket as Sophos responds.