React Native Version Mismatch

Getting the following message when i init a new project and then launch the x-code emulator. "React-Native Version Mismatch" Javascript Version 0.50.1 Native version: 0.50.0

Make sure you have rebuilt the native code...

Does anyone know what is going on here and can help me?

Thanks!

This is what I've done with it:

Close all terminals and run build again.

You may forgot to close nodejs terminal from another project, and they happen to have installed different react version.

So the code fetch from nodejs server conflicts with native one.

Just go to your android/app/build.gradle and then add to the dependencies section:

dependencies{
compile ("com.facebook.react:react-native:0.50.3") { force = true } 
}

/// the react native version can be found in package.json

In case you created your react-native app using create-react-native-app. You should have a app.json (expo). and a package.json file, check if the expo versions match and change accordingly. For example in my case the problem was that in the app.json file I had a 25.0.0 version for the expo sdkVersion attribute, I change that to 23.0.0 and everything worked.

package.json:

"dependencies": {
    "expo": "^23.0.4",
    "react": "16.0.0",
    "react-native": "^0.50.4"
  }

app.json:

{
  "expo": {
    "sdkVersion": "23.0.0" // before was 25.0.0
  }
}

just force react native version in your android's app level gradle file, in the dependencies section.

compile ("com.facebook.react:react-native:0.52.0") { force = true }

worked for me

In your build.gradle file add the following

implementation ("com.facebook.react:react-native:0.51.0") {
    force = true;
}

replace 0.51.0 with the version in your package.json

I've never seen this error before, but whenever I can't get Xcode and React-Native to play well together, I do a couple of things. Check what version of Xcode I'm working with. If it needs to be updated, I update it. Then clearing watchman and the cache are the second place I go. I don't use the reset cache command. It always says that I need to verify the cache, so I skip that (you can do it though, I just get confused). I use rm -rf $TMPDIR/react-* to get rid of any cached builds. If that doesn't work, I try to build the app in Xcode, then work my way from there, to build it with react-native run-ios. With this error message, it seems you might start by trying to build it with Xcode. Hope that helps...let me know your progress with it. Good luck! (Also, you could update to RN 0.51 as another attempt to get your versions synced.)

I had this problem for the longest time and none of the above solutions helped. I was in the middle of upgrading react native in a create-react-native-app project until I found out that not all versions of Expo support the latest React Native.

Found this page linked in the documentation that shows which version combinations of React Native, React, and Expo are officially supported:

Source: https://github.com/react-community/create-react-native-app/blob/master/VERSIONS.md

Editing the app.json and package.json files to match the corresponding versions and running npm install got everything working again.

Try installing the dependencies again. That worked for me-

1.) yarn/npm install
2.) yarn/npm start --reset-cache

If you're running your React Native app through Expo, upgrading React Native is liable to cause this error (as noted at https://github.com/expo/expo/issues/923).

If that's your scenario, your options are:

1. Bump Expo (which is listed in your package.json) to a version that is compatible with your React Native version (if one exists, which may not be the case - judging by the linked issue, I figure that Expo support trails React Native releases).
2. Discard your changes, delete and reinstall your Node modules, Eject from Expo, and then (after checking that you can still run your app post-ejection) try your upgrade again.

For Android developers who couldn't get it fixed by just closing and rebuilding, Manually uninstall the app on the emulator/device.

For me it was due to react-native version in dependency section of package.json file. It was:

"dependencies": {
"expo": "^27.0.1",
"react": "16.3.1",
"react-native": "~0.55.0"
}

I chaged it to:

"dependencies": {
"expo": "^27.0.1",
"react": "16.3.1",
"react-native": "0.52.0"
}

Now it works fine.

For others with the same problem on iOS with CocoaPods:

I tried all of the solutions above, without luck. I have some packages with native dependencies in my project, and some of those needed pod modules being installed. The problem was that React was specified in my Podfile, but the React pod didn't automatically get upgraded by using react-native-git-upgrade.

The fix is to upgrade all installed pods, by running cd ios && pod install.

the fix we did was to make sure the ANDROID_HOME and PATH variables were set up prior to the build.

First, run the below two commands then the build the app for the device.

export ANDROID_HOME=/Users/username/MyFiles/applications/androidsdk export PATH=$PATH:$ANDROID_HOME/tools:$ANDROID_HOME/platform-tools

For me, I had to restart my computer, open the IDE(VS Code, Brackets, Sublime, etc) again and build the project

I also had this issue using Expo and iOS Simulator. What worked for me was erasing the Simulator in Hardware > Erase All Content and Settings...

This is not a fix, but in my case, I had multiple RN apps installed on my device and I was unknowingly attempting to 'Reload` from within the wrong application. (I'm developing two apps simultaneously at the moment) So make sure you're in the correct application!

Try changing the version of your react-native specified in your package.json (under dependencies - react-native) to the same as 'Native Version' shown in the error message. Then run 'npm install' again.

I have got the same issue while building my react native app for android and I did the following which worked for me.

The "JavaScript version 0.50.1" in the error console is the react-native version in your package.json file. Make sure it is the same version as "Native version 0.50.0" in the error console.

1. I have Updated the react-native version to the "Native Version 0.50.0" as prompted in the error console.
2. Rebuild the app react-native run-android.

Make sure also that the wifi is enabled in your emulator

In my case installing a new virtual device helped. Now I am using 1 device per app.

I am using a physical device, in my case this solved the problem:

1. Uninstalling the app
2. lsof -i :8081
3. kill -9 PID
4. Rebuild the app react-native run-android

Opene projectdir/android/app/build.gradle

Try:

compile("com.facebook.react:react-native:0.51.0") { force = true }

Instead of compile "com.facebook.react:react-native:0.51.0" { force = true }

Ref.: Link

My solution is

1. Upgrade React-Native

2. Delete all node_modules

3. Modify package.json (react native with latest version)
4. NPM install