When upgrading from 2.0.0-rc.16 to 2.0.0-rc.17 my application fails to start, and gives the following error.

TypeError
Cannot read property 'extend' of undefined

I have confirmed this by creating a brand new site by running the following command, and choosing the bootstrap framework

npx create-nuxt-app example

Application is using nuxt 2.6.1 and bootstrap 4.3.1
Nodejs is 11.9.0 and npm 6.5.0
Test in Firefox 66.0.2 and Chrome 73.0.3683.103 running Windows 10 x64