To revert to vue 2.3.4 (ie. the latest 2.3.x)locate the vue folder in your node_modules folder and delete it. open your app’s package.json and set the vue version to 2.3.4, excluding major versions, like so: "vue": "~2.3.4" run npm i in your app’s folder (optional, but recommended) run quasar dev, open your app in Chrome and use Vue-tools to check for the currently used Vue.js version.
Tilde (~) means it will NOT automatically get upgraded to the next minor version (eg. the current 2.4.2 which still has a bug preventing quasar from running).
The usual caret (^) meant we would automatically upgrade to minor versions like 2.4.x, 2.5.x etc. up to but excluding the next major versions (3.x.x etc)
Bullet point 4 is also a good way to know which Vue version is really running even before decide to you attempt the fix, since your app’s package.json can be deceiving, and fishing Vue’s package.json file out of node_modules to look for the version is quite annoying.