We expect the Dart 2 release to graduate to stable in the immediate future. Thus, it’s critical that you migrate your code — especially any packages you have published — to be Dart 2 compatible now!
There are three main aspects to this:
Make sure your code passes Dart 2 analysis (details). We recommend you also pay attention to hints — for example, to prepare for deprecations.
Run tests to make sure your code passes Dart 2 runtime checks (details).
Update the upper bound of the SDK constraint of your packages to <3.0.0 (details).
We strongly encourage all package authors to do this work as soon as possible. To support this work, we’ve made some enhancements to the Pub site to better show potential issues. See our Medium post for full details.