When updating Node with NVM you can grab a list of the latest remotely available versions with nvm ls-remote --lts.
When updating to a new version - v6.9.4, for example - you can copy over your pre-existing packages during the install with nvm install v6.9.4 --lts --reinstall-packages-from=v6.9.2
Finally, preset your console default to the new node installation using nvm alias default v6.9.4.