I can see the version of generator-webapp that I want in github but when I do an npm install, it seems to be giving me an older version.
I note that the version number in the packages.json hasn't been updated in the last few changes. I don't know if that is a factor.
The version you install with npm must be published on npmjs.com For example, last published generator-webapp version is 0.5.1
If you want the last version from github Use that
npm install git+https://[email protected]/npm/npm.git
(with the repo you want of course)