$ bower install

$ gulp update
[10:31:22] Warning: gulp version mismatch:
[10:31:22] Global gulp is 3.9.0
[10:31:22] Local gulp is 3.8.11

$ gulp -v
[10:39:05] CLI version 3.9.0
[10:39:05] Local version 3.8.11

$ npm install gulp@3.9.0 --save