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Before a React Native upgrade, how do you check that the app's native libraries will work with the target version?

level: middleimportance: should knowfreq 40%

answer

  1. inventory packages with native code
  2. README compatibility tables and changelogs
  3. React Native Directory as a first stop
  4. 0.87 needs library compileSdk 34+
  5. prove it with a clean build

basics

~20 s

List every dependency that ships native code, check each one's README, changelog and React Native Directory entry for support of the target version, note required upgrades or blockers, then prove it with a clean iOS and Android build on a branch.

solid answer

~40 s

The risk in an upgrade is rarely JavaScript-only packages; it is libraries with **native code**, which compile against React Native's headers and Gradle setup. I list those dependencies, then for each one check its README and changelog for the React Native versions it supports, and use **React Native Directory**, which the docs call the first place to look for libraries, to confirm platform support. The docs note the latest library version usually targets the latest React Native, while older apps must pick the version the README names. I also check the target release's requirements that libraries must meet: 0.87, for instance, requires libraries to compile against Android SDK 34 or newer. Libraries without support become blockers, replacements or patches, and a clean build of both platforms on a branch is the final proof.

go deeper

for a junior

Recall that libraries with native code are the upgrade risk, and that READMEs and React Native Directory tell you which versions they support.

for a middle

Explain how to inventory native dependencies, read compatibility statements and match library versions to the target React Native version.

for a senior

Decide per blocker whether to wait, replace, patch or remove, and prove compatibility with clean builds before committing to a date.

for a principal

Set a dependency policy that weighs maintenance health before adoption, so future upgrades are not held hostage by one abandoned library.

## Why libraries are the real risk React Native libraries come in two kinds: - **JavaScript-only** packages, which run in any compatible JavaScript environment and rarely break on a React Native upgrade; - packages with **native code** (an `ios/` folder with a podspec, an `android/` folder with Gradle files), which compile against React Native's own headers, Gradle plugin and build settings. A React Native minor can change exactly those native surfaces: header layout, Gradle and Kotlin versions, minimum SDKs, removed native APIs. A library that built yesterday can fail to compile after the upgrade, or compile and crash at runtime. ## Step 1: inventory Build a table of every dependency with native code. Useful columns: | Library | Current version | Supports target? | Required version | Notes | |---|---|---|---|---| | camera library | 4.x | yes, from 4.6 | 4.6.2 | update with the upgrade | | legacy maps wrapper | 1.x | unknown | none | blocker, investigate | The native folders of `node_modules` and the autolinking output tell you which packages have native code. ## Step 2: check each library For every row, check in this order: 1. The library's **README** and **changelog** or release notes: many state a compatibility table or the minimum and maximum React Native versions per release. 2. **React Native Directory**, which the React Native docs call the first place to look for libraries; it lets you filter by platform compatibility, such as iOS, Android, Web and Windows. 3. Open **issues** mentioning the target version, which often reveal breakages before a release note does. The React Native docs summarise the rule: the latest version of a library is typically compatible with the latest React Native; an app on an older version should follow the README to find which library version to install. ## Step 3: check the release's requirements on libraries Each release post lists requirements that affect libraries, not just apps. Examples from 0.87: - libraries must compile against **Android SDK 34 or newer** (`minCompileSdk` is now 34); - the **minimum Kotlin version** is 2.0; - iOS headers moved into header-only XCFrameworks, so bare includes need the namespace, for example `<React/RCTAppDelegate.h>`. A library that has not been updated in a year is the one most likely to trip over these. ## Step 4: decide per blocker For a library with no compatible release: - **wait**: stop the upgrade at the highest version it supports, if that version is still supported; - **replace** it with a maintained alternative, searching Directory and npm; - **patch** it locally, as a short-lived measure with an owner and a removal date; - **remove** the feature or reimplement it, if the library is abandoned. ## Step 5: prove it Inventory is a prediction; the build is the test. On an upgrade branch: - install packages, run `pod install`, and clean-build both platforms; - run unit tests and at least a smoke pass through screens that use each native library; - read build warnings: deprecation warnings from libraries are the next upgrade's errors. ## A habit that makes this cheap Keep the inventory in the repo and review it when adding a dependency. A library with native code, few maintainers and no stated React Native support is a future upgrade blocker, and that is best known before it is installed. ## Signals that a native library will block future upgrades Most blockers are visible long before an upgrade starts. Warning signs worth recording in the inventory: - the README states support only for React Native versions that are already unsupported; - recent releases did not follow the last two or three React Native minors; - open issues about the latest React Native version have no response from maintainers; - the library still depends on APIs React Native has deprecated or removed, such as legacy architecture-only code paths; - its Android build pins an old compile SDK or Kotlin version. A library with several of these signs should be replaced on your schedule, before a React Native release forces the decision on the release's schedule.

  • Why are JavaScript-only packages rarely a problem in a React Native upgrade?
    They do not compile against React Native's native headers, Gradle plugin or SDK minimums, which are what minors most often change. They can still break on a removed JavaScript API or a changed type, which the type checker and tests will show, but they cannot fail the native build.
  • In React Native 0.87, why could an older library fail an Android build that worked on 0.86?
    0.87 raised `minCompileSdk` to 34, so libraries must compile against Android SDK 34 or newer, and raised the minimum Kotlin version to 2.0. A library still configured for an older compile SDK or Kotlin fails until it is updated or patched.

saying these in an interview costs you the question

  • If npm install succeeds, every library is compatible
  • JavaScript-only packages are the main upgrade risk
  • An abandoned native library will keep compiling on future versions
  • The latest library release always supports older React Native versions