[Cthulhu_]

Re: nodeJS versions, I'd go with something like "Install NodeJS, this book was written with version x.y.z"; I don't think JS will become backwards incompatible in the near future, so as long as the book doesn't contain experimental or unofficial JS features, it should be fine for the next 5-10 years.

[rapind]

Anecdotal I suppose, but I have an app that was written for node 5 and it doesn't work on 6+. I'm sure I could figure out and upgrade it, but it's not too high on the priorities yet thanks to nvm. Oh, and it's not the code, it's one or more of the npm modules.

[pitaj]

Odds are that it is a native module. That's unfortunate, but there is a plan in place to make a consistent native module API: https://github.com/nodejs/abi-stable-node