I saw that QtWebKit which provide the headless browser for PhantomJS is outdated. QtWebEngine is the new way to go which is developed heavilly. When I now look at the compat table for PJS I saw arround 10% for ES6 and wondering how this could work in the future. Isn't it a good idea to switch to the future proof technology? Or what is your motivation for the future with PS before it uses very outdated technologies?

And I have an additional question: I know a lot of WebKit functionality is implemented by the browser. But which steps are needed to upgrade to support the ES6 syntax?