Under most circumstances, migrating between versions should be done by following these commands
rm -rf node_modules
npm run init
Specific version migrating
For major versions, outlined below are the steps and precautions when updating versions
Updating from 8.x to 9.x
This update modified the file name the JS file for development.
You'll need to change the name of the js file in /src/index.html from 'bundle.js' to 'index.js'