Due to some complications with 3.27's migration to use real modules (and the resulting massive number of deprecations being triggered) we are not 100% certain (yet) that 4.0 will be the version just after v3.28.

In order to move ahead with v4.0 cleanup efforts (like this one), I've pushed a new branch that can serve as the target for breaking change PR's: https://github.com/emberjs/ember.js/tree/v4-cleanup.

I've updated this PR to target that branch, can you rebase against that branch and push an update?

# starting from this PR's branch

git fetch origin
git rebase origin/v4-cleanup

# fix any conflicts

# push the rebase
git push -f

Thank you for helping us push things forward!