Knockout.js Isn’t Dead. It’s Just Not Alive Either.

It’s not often you find a JavaScript framework that’s neither active nor officially end-of-life. But that’s exactly where Knockout.js lives: caught in a strange state of framework limbo, quietly powering tens of thousands of production apps and websites… while active maintenance appears elusive.

So is Knockout.js dead?

Yes. Functionally. But also… no.

Let’s break it down.

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The Knockout.js Timeline: Signs of Life, Signs of Death

Knockout.js peaked in the early 2010s as a lightweight MVVM library for building reactive UIs, leading the charge for many other frontends frameworks that came after.. But fast-forward to 2025, and the signs aren’t great:

• Last release: 3.5.1, July 2021
  
  
• No future roadmap
  
  
• No active triage on GitHub (over 300 open issues)
  
  
• No CVE reporting or patching process
  
  
• No formal EOL announcement
  
  
• ~20,000 weekly downloads on npm
  
  

It’s the software equivalent of Schrödinger’s cat: technically installable, functionally abandoned.

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Why Is Knockout Still Around?

Blame inertia. Knockout is still:

• Bundled in older .NET-based CMS platforms like DNN and legacy SharePoint SPAs
  
  
• Used in internal enterprise apps that haven’t migrated
  
  
• Maintained via private forks by corporate teams with no plans (or budget) to rewrite
  
  
• Present in government and high-traffic sites like Stack Overflow, Royal Mail, and more
  
  

Frameworks may die, but enterprise dependencies are forever.

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The Real Problem: No Patches, No Protections

While Knockout’s minimalist design kept it relatively secure, there’s a real XSS vulnerability (CVE-2019-14862) that still affects every version before 3.5.0—and those versions were never patched.

If you’re stuck on 3.4.2 (many are), you carry a known security risk. And since the core team never issued backports or a CVE management process, there’s no official fix coming.

Pair that with other risky bedfellows—like jQuery 1.x, Bootstrap 3, and RequireJS—and you’ve got a transitive vulnerability soup.

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Enter: HeroDevs Never-Ending Support for Knockout.js

We’re used to this pattern: a framework drifts into maintenance purgatory, but real companies still depend on it. That’s where Never-Ending Support (NES) for Knockout.js comes in.

With Knockout NES, we’ll provide:

• Security patches for legacy versions like 2.3.0 and 3.4.2
  
  
• Drop-in replacements for unpatched builds
  
  
• Long-tail CVE monitoring for a framework no one else is watching
  
  
• Compliance assurance for teams under audit pressure
  
  
• Compatibility updates to keep Knockout usable in modern CI/CD pipelines
  
  

You keep your frontend stable, compliant, and online, without rewriting from scratch.

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Why Now?

Because this is the last stop, Knockout won’t get a surprise revival. There’s likely no v4.0 in the wings. And while your KO app might “just work” today, it’s unsupported, vulnerable, and out of compliance.

You can keep holding your breath the boat will stop leaking—or you can plug the hole.

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Let’s Be Real

Frameworks like Knockout rarely die with a bang. They fade. Quietly. While still running in critical infrastructure at major institutions.

We built HeroDevs to serve exactly this moment. We don’t just support dead frameworks—we keep them safe, secure, and sustainable for the teams still running them.

If Knockout is still in your stack, it’s time to give it a second life—with NES.

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