Block-scoped declarations (let, const, function, class) not yet supported outside strict mode

[typeoneerror]

Just updated from 0.8.1 to 0.9.2 and now get this when I start my ember app. Is watson backwards compatible with ember-cli 2.8.x or do I need to upgrade ember and other components to use this? I'm going to try to use ember watson outside of cli first, but here's the error I have in case anyone can help.

node@4.8.11
npm@2.15.11
ember@2.8.0

SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:373:25)
    at Object.Module._extensions..js (module.js:416:10)
    at Module.load (module.js:343:32)
    at Function.Module._load (module.js:300:12)
    at Module.require (module.js:353:17)
    at require (internal/module.js:12:17)
    at Object.<anonymous> (/Users/typeoneerror/Dev/doki.io/frontend/node_modules/ember-watson/lib/watson.js:19:34)
    at Module._compile (module.js:409:26)
    at Object.Module._extensions..js (module.js:416:10)

[typeoneerror]

More specifics after installing globally:

/Users/typeoneerror/.nvm/versions/node/v4.8.1/lib/node_modules/ember-watson/lib/formulas/convert-tests-to-async-await.js:61
  let callback = node.expression.arguments[1];
  ^^^

points here:

https://github.com/abuiles/ember-watson/blob/master/lib/formulas/convert-tests-to-async-await.js#L61

I got money that it's because I'm node 4.x?

[typeoneerror]

Yep, 😢. I'm having the hardest time getting our app to work on newer versions of node, so I was hoping to not have to upgrade, but looks like I may be hosed.

~/Dev/doki.io/frontend (feature/ember-cli-update) $ nvm use lts/carbon
Now using node v8.9.3 (npm v5.5.1)
~/Dev/doki.io/frontend (feature/ember-cli-update) $ npm install -g ember-watson
npm WARN deprecated minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated babel-preset-es2015@6.24.1: 🙌  Thanks for using Babel: we recommend using babel-preset-env now: please read babeljs.io/env to update!
/Users/typeoneerror/.nvm/versions/node/v8.9.3/bin/ember-watson -> /Users/typeoneerror/.nvm/versions/node/v8.9.3/lib/node_modules/ember-watson/bin/ember-watson
+ ember-watson@0.9.1
added 292 packages in 11.806s
~/Dev/doki.io/frontend (feature/ember-cli-update) $ ember-watson --version
0.9.1

[knownasilya]

This should be fixable in watson by adding 'use strict'; to that file.