$ chef-client -version Chef: 12.4.1
$ curl -L https://www.opscode.com/chef/install.sh | sudo bash
$ chef-client -version Chef: 13.2.20
or
knife ssh 'name:[* TO *]' 'curl -L https://www.opscode.com/chef/install.sh | sudo bash'
https://stackoverflow.com/questions/20205889/how-to-update-the-chef-client-version