The lower bound of “sdk: ‘>=2.1.0 <3.0.0′” must be 2.12.0 or higher to enable null safety
You must update your flutter/dart version like this (in your pubspec.yaml): In order to enable null safety, the lower bound of the SDK version should be 2.12.0 or higher. The provided requirement, “sdk: ‘>=2.1.0 <3.0.0′”, does not meet this criteria, as the minimum required version is 2.12.0. To enable null safety, you should update the SDK version to at least 2.12.0. environment: sdk: “>=2.7.0 <3.0.0” You must update your flutter/dart version like this (in your pubspec.yaml): Be prepared to make
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