npm stands for "no problem meatbag", not "node package manager" ;)

It's the package manager for javascript and will continue to be. The module system in io.js is not going to be changing anytime soon.

If you mean which version, the changelog says version 2.5.1 in that release.

If you're asking if io.js is using a different npm, no it's using the same as Node.

You use io.js pretty much like "another version of node" which is why you'd use nvm if you want to have both io and node on the same system (same way you'd use nvm to have two versions of node on the same system) or just straight upgrade/replace, like replacing 0.10 by 0.12.

it's still NPM, even comes with io.js download. Works just like Node.