You are using an unsupported ember-cli-babel version,decorators will not be stripped automatically

[allthesignals]

I'm trying to upgrade Ember from 3.4 to 3.8. I'm seeing this warning:

WARNING: @ember-decorators/argument: You are using an unsupported ember-cli-babel version,decorators will not be stripped automatically
Not a directory: /Users/mgardner/Source/labs-applicant-maps/node_modules/yetch/dist/yetch-polyfill.js

Okay, babel is unsupported, but I'm seeing this as my version of babel:
"ember-cli-babel": "7.5.0",

How do I address this? I've tried using ember dependency-lint, but it doesn't turn up ember-cli-babel issues. Why?

After fishing around yarn-lock.json, I'm seeing these different versions of ember-cli-babel:

"ember-cli-babel": "6.17.2"
"ember-cli-babel": "7.1.3"
"ember-cli-babel": "6.14.1"

Does Babel need to be the same version for decorators to work?

If I remove argument decorators, I see an error about yetch:

Not a directory: /Users/mgardner/Source/labs-applicant-maps/node_modules/yetch/dist/yetch-polyfill.js

Any thoughts?

[jelhan]

Upgrading to v1.0.0-beta.2 fixed this for me.