Wrinkl v. Slack: USPTO Reexamination Stays Messaging Patent Case

Introduction

A patent infringement lawsuit targeting one of the world’s most widely used enterprise messaging platforms has been brought to a standstill—not by a court ruling on the merits, but by a coordinated multi-front challenge at the U.S. Patent and Trademark Office. In Wrinkl, Inc. v. Slack Technologies, LLC and Salesforce, Inc. (Case No. 1:24-cv-00620, D. Del.), the Delaware District Court administratively closed the case on January 30, 2025, after granting an unopposed motion to stay pending the resolution of one ex parte reexamination and two inter partes reviews (IPRs) targeting every claim of the asserted patent.

This outcome illustrates a defining trend in modern patent litigation: defendants leveraging USPTO post-grant proceedings as a first-line litigation shield. For patent attorneys, IP professionals, and R&D teams operating in the enterprise software and communications technology space, the strategic mechanics of this case offer critical lessons in both offensive patent assertion and defensive patent invalidity tactics.

Case Overview

The Parties

The Patent at Issue

The sole patent asserted in this action is U.S. Patent No. 11,973,731 B2 (Application No. 18/535,572), directed to communications technology underlying collaborative messaging platforms. The ‘731 patent covers innovations relevant to how messaging systems manage, organize, or deliver communications—the functional core of the Slack platform.

The Accused Product

Wrinkl accused the Slack Platform of infringing the ‘731 patent. Given Slack’s enterprise-scale deployment and Salesforce’s integration of Slack across its CRM and cloud ecosystem, the commercial stakes of this dispute were substantial.

Legal Representation

Fish & Richardson PC represented Wrinkl, with attorneys Adam J. Kessel, Frank E. Scherkenbach, Lawrence K. Kolodney, AnnaMartina Tyreus Hufnal, Alexander Pechette, Kelly A. Del Dotto, and Taylor Reeves leading the plaintiff’s team. Fish & Richardson is consistently ranked among the most active patent litigation firms in the United States.

Morris, Nichols, Arsht & Tunnell LLP represented Slack and Salesforce, fielding Brock S. Weber, Christopher Kao, Rodger Dallery Smith II, Theresa A. Roozen, and Lucinda Cole Cucuzzella—a seasoned Delaware IP defense team with deep familiarity in the district.

Litigation Timeline & Procedural History

Wrinkl filed suit on May 23, 2024, in the District of Delaware—a preferred venue for patent plaintiffs given its experienced judiciary, established local patent rules, and predictable case management. The case was assigned to Judge John Campbell Barker.

The litigation proceeded for approximately 252 days before being administratively closed on January 30, 2025. By patent litigation standards, this is a relatively compressed timeline to reach a stay disposition, suggesting that the defendants moved aggressively and early to initiate USPTO proceedings as a parallel track strategy.

Critically, the defendants filed petitions for IPR2024-01489 and IPR2024-01490 before the Patent Trial and Appeal Board (PTAB), and separately initiated Ex Parte Reexamination Control No. 90/019,710—an unusually coordinated and comprehensive USPTO challenge encompassing all claims of the ‘731 patent. This multi-proceeding approach signaled a well-resourced defense strategy designed to neutralize the patent before any district court merits determination.

The motion to stay was filed at Docket Entry 58 and was notably unopposed, a detail that carries strategic significance discussed below.

The Verdict & Legal Analysis

Outcome

The court granted the defendants’ unopposed motion to stay and ordered the case administratively closed pending the outcome of the three parallel USPTO proceedings targeting the ‘731 patent. The court’s order requires defendants to file a notice within seven days of resolution of the USPTO proceedings so the case may be reopened and further action taken. No damages were awarded, and no injunctive relief was issued. The case status is recorded as closed at the district court level, though it remains substantively unresolved pending USPTO determinations.

Verdict Cause Analysis

The legal basis for the stay is well-established under federal patent practice. Courts apply a three-factor balancing test when evaluating stay requests pending USPTO review: (1) whether discovery is complete and a trial date has been set; (2) whether a stay will simplify the issues in question; and (3) whether a stay would unduly prejudice or present a tactical disadvantage to the non-moving party.

Here, all three factors favored a stay. The case was at an early procedural stage with no trial date set. Because all claims of the sole asserted patent were under challenge at the USPTO through both ex parte reexamination and two IPR petitions, any PTAB or examiner action—cancellation, amendment, or confirmation—would directly simplify or potentially eliminate the district court litigation. Most compellingly, Wrinkl’s decision not to oppose the motion effectively removed the prejudice factor from the court’s analysis, expediting the grant.

The choice of ex parte reexamination alongside dual IPRs is strategically notable. IPRs are limited to prior art challenges based on patents and printed publications, while ex parte reexamination can be initiated on a broader basis and does not carry the same estoppel consequences for the requester. Using all three proceedings simultaneously maximizes the probability of patent claim disruption while managing estoppel risk.

Legal Significance

This case reinforces the pivotal role of PTAB proceedings as a litigation management tool in complex patent disputes. The Delaware District Court’s swift grant of an unopposed stay—administratively closing the docket within eight months of filing—demonstrates how proactively initiated USPTO challenges can effectively pause district court proceedings before any significant merits-based rulings occur.

For the ‘731 patent specifically, the outcome of IPR2024-01489, IPR2024-01490, and Reexamination No. 90/019,710 will be determinative. If any claims survive, Wrinkl may reassert them with potentially amended scope; if canceled, the litigation ends.

Strategic Takeaways

For patent holders: The unopposed nature of the stay suggests Wrinkl may have been tactically conserving resources or evaluating claim amendment options through reexamination. Patent prosecutors should anticipate parallel USPTO challenges when asserting patents against large technology defendants and build continuation strategies accordingly.

For accused infringers: Slack and Salesforce’s approach—filing two IPRs and a reexamination within months of being served—represents a textbook early-stage invalidation strategy. When a patent’s entire claim set can be challenged, doing so promptly and comprehensively before district court scheduling orders issue is highly effective.

For R&D teams: Companies integrating messaging or collaboration platform features should monitor the ‘731 patent’s reexamination and IPR outcomes, as surviving or amended claims could define enforceable boundaries in this technology space.

Industry & Competitive Implications

This case sits at the intersection of two significant trends: the increasing assertion of patents against enterprise SaaS platforms and the strategic use of PTAB proceedings to manage litigation exposure. Slack’s position as a mission-critical enterprise tool makes it a recurring target for patent holders, and Salesforce’s resources enable aggressive USPTO-based defense strategies unavailable to smaller defendants.

For the broader communications technology and enterprise software sector, this case signals that patent claims touching core messaging functionality—routing, delivery, organization, or notification systems—will face rigorous validity scrutiny when asserted against market-leading platforms. Licensing negotiations in this space should account for the high probability of IPR exposure when patents cover foundational platform features.

The coordination between ex parte reexamination and dual IPRs also reflects a maturation in defense-side patent strategy: using complementary USPTO tracks to create multiple overlapping threats to patent validity, complicating the patent owner’s ability to maintain enforceable claims across all fronts.

❓ Frequently Asked Questions

What patent was at issue in Wrinkl v. Slack Technologies?

The sole patent asserted was U.S. Patent No. 11,973,731 B2 (Application No. 18/535,572), a communications technology patent directed at messaging platform functionality.

Why was the case administratively closed?

The Delaware District Court granted defendants’ unopposed motion to stay pending resolution of Ex Parte Reexamination No. 90/019,710 and IPR proceedings Nos. IPR2024-01489 and IPR2024-01490, all of which challenge every claim of the ‘731 patent at the USPTO.

How might this case affect messaging technology patent litigation?

The outcome of the USPTO proceedings will define the enforceability and scope of the ‘731 patent, potentially setting parameters for similar assertion campaigns against enterprise communications platforms.

Explore related cases in communications technology patent litigation or subscribe for patent litigation updates from the Delaware District Court and PTAB. For case-specific analysis, consult with a qualified IP attorney.

Reference resources: USPTO Patent Center | PACER Federal Case Search | PTAB Public Portal