Flutter is actively working on the underlying web support and we're trying to follow suit. If you get this error message, it means that you're lagging behind with your Flutter installation: we're on version 3.19 right now and 3.13 — the one required by the plugin now — came out more than five months ago. You should really consider upgrading your Flutter right now.
If you're unable to do it for any reason, you can go back to the previous version of this plugin by removing the ^ in your pubspec.yaml:
flutter_dropzone: 3.0.12
Consider it temporary and work on the issue that keeps you from upgrading Flutter.
Flutter is actively working on the underlying web support and we're trying to follow suit. If you get this error message, it means that you're lagging behind with your Flutter installation: we're on version 3.19 right now and 3.13 — the one required by the plugin now — came out more than five months ago. You should really consider upgrading your Flutter right now.
If you're unable to do it for any reason, you can go back to the previous version of this plugin by removing the ^ in your
pubspec.yaml:Consider it temporary and work on the issue that keeps you from upgrading Flutter.
You should use version 4.0.x from now on.