There are hundreds of different SDKs available these days in the programming language of your choice that can do a number of things from facilitating features to helping quickly develop user interfaces. Flutter is one of the most common SDKs in modern-day programming. It’s developed by Google and makes creating cross-platform app development easy.
In this article, we’re talking about the “error: member not found: firebaseappplatform.verifyextends” issue in Flutter, its causes and what you can do to fix the problem.
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What causes this issue?
The error is mainly triggered when you upgrade your Flutter SDK version but the platform plugin remains on the older version. Alternatively, the error can also occur if the platform plugin version of Flutter isn’t compatible with the SDK version you’re using.
How to fix this?
Here are four fixes you can try out.
Update your download cache
The first thing you should do is upgrade your download cache for your Flutter SDK. You can do this by running a simple command given below.
flutter pub upgrade

Update Flutter
In case you’re using an experimental version, you need to update Flutter to a stable variant for your project to work properly. You can do this by running these commands one at a time:
flutter channel stable
flutter upgrade
Once you’re done, update the pub and you’re good to go.
flutter pub upgrade
Override dependencies
If upgrading the pub isn’t helping, you can manually override dependencies to fix any version mismatch issues. To do so, head over to your pubspect.yaml file and manually change the version number of your dependencies to the latest stable version available.

Clear the cache
Finally, you can also clear your Flutter cache to rebuild it and resolve any version mismatch issues in the process.
flutter clean
flutter pub get
Also read: How to fix Axioserror: Network error?