It is crucial to update Node.js to the most recent Long-Term Support (LTS) version for long-term maintenance, security, and performance. Nevertheless, many developers encounter unforeseen problems following an upgrade, such as builds failing, tests failing, or changes in production behavior.


To put it simply, these problems typically result from breaking changes. A breaking change occurs when a feature that was functional in the previous version of Node.js is no longer functional in the current version. Using straightforward language and real-world examples, this article demonstrates how developers can safely and early identify breaking changes when updating Node.js.

Recognize What Node.js "Breaking Change" Means
There are several ways that a breaking change can manifest:

  • APIs altered or eliminated
  • More stringent error handling or validation
  • Incompatibilities between dependencies
  • Modifications to the default behavior

For instance:
Code works in Node.js 16 → Fails in Node.js 20

Understanding that not all breaks are syntax errors helps developers debug faster.

Read Node.js LTS Release Notes First
Before upgrading, developers always review official Node.js release notes. These notes list deprecated features, removed APIs, and behavior changes.

What to look for:

  • Removed or deprecated APIs
  • Changes in default flags
  • Updated OpenSSL or V8 versions

Example workflow:
Read release notes → Identify risky changes → Prepare fixes

This step prevents surprises later.

Run the Application with the New Node.js Version Locally
The fastest way to detect breaking changes is running the app locally with the new LTS version.

Example:
node -v

node index.js
Common early signals include:

  • Startup crashes
  • Deprecation warnings
  • Runtime errors

Local testing catches obvious issues quickly.

Enable Strict Error and Warning Logs
Newer Node.js versions often log warnings more strictly.

Example:
node --trace-warnings index.js

This highlights deprecated APIs and unsafe patterns that may break in future releases.

Run Automated Test Suites
Automated tests are one of the most reliable ways to detect breaking changes.

Best practice:
Upgrade Node.js → Run all tests → Fix failures

Example:
npm test

If tests fail after the upgrade, the failures usually point directly to incompatible behavior.

Compare Behavior Using Multiple Node Versions
Developers often compare behavior between the old and new Node.js versions.

Example using version managers:
nvm use 18
npm test

nvm use 20
npm test

Differences in output or failures highlight breaking changes clearly.

Check Dependency Compatibility
Many breaking changes come from dependencies that do not yet support the new Node.js version.

Steps:

  • Check dependency release notes
  • Look for Node.js engine requirements
  • Upgrade incompatible packages


Example check:
npm outdated

Outdated dependencies are a common source of upgrade pain.

Watch for Native Module and Build Failures
Packages with native bindings often break during Node.js upgrades.

Common symptoms:

  • Build errors
  • Runtime crashes
  • Installation failures

Example:
npm install

If native modules fail, upgrading or rebuilding them usually resolves the issue.

Use Linting and Static Analysis Tools
Static analysis tools detect risky patterns that newer Node.js versions reject.

Example idea:
Lint warnings → Potential runtime break
Running linters after upgrade helps catch subtle issues early.

Monitor Runtime Behavior in Staging
Some breaking changes only appear under real traffic.

Best practice:
Deploy to staging → Monitor logs and metrics → Validate behavior

Watch for:

  • Memory usage changes
  • Performance regressions
  • Unexpected exceptions


Staging environments reduce production risk.
Enable Feature Flags for Risky Changes

For large applications, developers often guard risky changes behind feature flags.

Example concept:
New Node.js behavior → Feature flag → Gradual rollout

This allows fast rollback if issues appear.

Use Canary Releases in Production
Canary deployments expose a small portion of traffic to the new Node.js version.

Example approach:
5% traffic → New Node.js → Monitor → Expand rollout
This limits impact if breaking changes are missed.

Monitor Errors After Upgrade
After deployment, close monitoring is critical.

Key signals:

  • Error rate increases
  • New exception types
  • Slower response times

Example:
Upgrade complete → Metrics spike → Investigate immediately

Early detection prevents major outages.

Keep Rollback Options Ready
Even with careful preparation, some issues appear late.

Best practice:
Upgrade → Issue detected → Roll back Node.js version

Rollback readiness is a core part of safe upgrades.

Common Mistakes to Avoid
Avoid these upgrade mistakes:

  • Skipping tests
  • Ignoring warnings
  • Upgrading Node.js and dependencies together without validation
  • Deploying directly to production
  • Incremental and controlled upgrades work best.

Summary
After updating Node.js to the most recent LTS, developers examine release notes, run apps locally, enable strict warnings, run automated tests, verify dependency compatibility, and validate behavior in staging environments to find breaking changes. Risk is further decreased by employing canary releases, closely monitoring production, and comparing behavior across Node versions. Teams can reliably embrace new Node.js LTS versions without interfering with production systems thanks to a controlled upgrading process.