// UPGRADE
ng v

sudo npm uninstall -g angular-cli
sudo npm uninstall angular-cli

sudo npm cache verify

sudo npm install -g @angular/cli@latest
sudo npm install @angular/cli@latest


// DOWNGRAGE
// old version (I'm using 6.1.5 to test)
sudo npm uninstall -g angular-cli
sudo npm uninstall angular-cli

sudo npm cache verify

sudo npm install -g @angular/cli@6.1.5
sudo npm install @angular/cli@6.1.5

ng v