Why Rails upgrades are harder than you think

Rails upgrades seem like they should be simple. In theory, you just bump the version number, resolve some gem conflicts, and call it a day.

In reality? The upgrade drags on for months, feature development slows to a crawl, and your team starts muttering things like “Maybe we should just rewrite this in Elixir” under their breath.

We’ve been in the trenches of some of the biggest Rails upgrades in the world—helping companies like GitHub, Gusto, and Zendesk avoid upgrade hell. 

We’ve seen firsthand how in-house teams underestimate the complexity, overpromise on timelines, and ultimately spend way too much time and energy just trying to make their app work again.

Let’s talk about why Rails upgrades are trickier than they look, the hidden costs of attempting them in-house, and why so many companies end up calling us to save the day.

The hidden complexity of a Rails upgrade

Let’s be real: Most engineering leaders don’t want to do a Rails upgrade. They have to. Maybe they’ve outgrown an older version, maybe they need security fixes, or maybe someone on the compliance team just discovered that running an unsupported framework isn’t exactly best practice.

Whatever the reason, leadership says, "We need to upgrade."

So your team starts planning. And this is where things go off the rails (pun fully intended).

What gets underestimated every time:

Breaking changes lurk everywhere. Each new Rails version comes with deprecations, behavior shifts, and subtle gotchas that can break your app in weird, unexpected ways.

Your dependencies don’t care about your timeline. That one gem your app critically depends on? Yeah, it hasn't been updated in four years, and now you're rewriting half your codebase just to replace it.

Your test suite isn’t as good as you thought. If your test coverage is spotty, you won’t know what you broke until it’s in production—where your customers will kindly inform you via support tickets and Twitter rants.

Your app isn’t just Rails. Database versions, background jobs, third-party integrations—these all have to be audited and tested to avoid nasty surprises post-upgrade.

Feature work grinds to a halt. Your best engineers get pulled into upgrade purgatory, leaving the rest of the team to either twiddle their thumbs or try (and fail) to ship new features without them.

Upgrades can break brand-new features. Just because an upgrade is “done” doesn’t mean it stays done—ongoing feature work can introduce subtle incompatibilities that force teams to revisit completed upgrades.

Upgrading isn’t just technical—it’s political. Every risky or disruptive change needs buy-in from stakeholders who may not fully understand the complexity. Without clear communication, upgrades get derailed fast.

This is why a “quick upgrade” turns into a multi-month slog. By the time the app is finally running on the new version, everyone is exhausted, the codebase is messier than before, and leadership is wondering why this took longer than the last actual product launch.

The real cost of upgrading Rails in-house

So let’s talk about what this upgrade actually costs when you try to do it yourself.

Lost productivity. Every month your team spends upgrading is a month they aren’t building new features, fixing customer pain points, or improving performance.

Missed deadlines. Upgrades rarely go according to plan. Dependencies break, regressions appear, and suddenly your “quick upgrade” is pushing back product roadmaps.

Developer burnout. Engineers don’t exactly love spending months fighting deprecation warnings. Upgrades are tedious, high-pressure, and feel like thankless work—especially when leadership keeps asking, “Isn’t it done yet?”

Post-upgrade surprises. Even if you technically finish the upgrade, you’re not out of the woods. Performance issues, unexpected behavior changes, and sneaky bugs have a way of surfacing after you go live.

It’s going to get messy. Let’s be honest—no one wants to touch the cruftiest parts of the codebase. But upgrades force teams to dig into technical debt that’s been ignored for years, which only adds to the time and complexity.

The bottom line? If you don’t approach an upgrade strategically, it will cost you more time, money, and stress than you expect.

This is why companies like GitHub, Gusto, and Zendesk called us when they needed their Rails upgrades done right.

‍How Test Double makes Rails upgrades actually manageable

Our approach is different because we don’t just get the upgrade done—we make sure your app is in better shape than when we started.

Here’s how we do it:

We plan for real-world constraints. We don’t just blindly bump versions—we map out the safest upgrade path, minimize disruptions, and keep feature work moving.

We proceed in an incremental and interruptible fashion. If something comes up, your team isn’t locked in upgrade purgatory for six months—you won’t lose the work we’ve done.

We identify and fix hidden tech debt. Upgrades are a great opportunity to clean up legacy code, improve test coverage, and set your team up for long-term success.

We communicate effectively. We make sure everyone who needs to know—engineering, product, leadership—understands why a change is risky, how it will affect them, and how we’ll mitigate issues.

We hit deadlines without cutting corners. Gusto needed their upgrade delivered on time and under budget. We made it happen (and fixed 1,700 test failures along the way).

We leave your team stronger than before. Our goal isn’t just to finish the upgrade—it’s to make sure your engineers have the knowledge and techniques to avoid falling three versions behind again.

As GitHub’s Eileen Uchitelle—who, by the way, is literally a Ruby core maintainer—famously put it: “Hot take: just have Test Double build all your stuff.”

We couldn’t have said it better ourselves.

Thinking about a Rails upgrade? Let’s talk.

If your team is staring down a Rails upgrade and wondering “How bad is this going to be?”—we should chat.

We’ve done this for some of the biggest Rails codebases in the world. We know the pitfalls, we know how to avoid them, and we know how to make this way less painful for your team.

So before your senior engineers mysteriously disappear for “just a quick break” (only to return six months later after an existential crisis), let’s talk.

We can help make your upgrade smooth, fast, and drama-free. Contact us now.