i have an app that was written for 0.8 three years ago. it is running on 4.2 with no modification. (it doesn't use any binary add ons). javascript is almost entirely backwards compatible because they can't break the web.

Other apps that require binary add ons required me to install the latest versions from NPM -- one one of them required ANY changes to how the API was called and it was extremely minor.

Waiting 2 years to upgrade the engine your code is running on is not horrible and requires much less pain