Recently, Ghost update to version 2.0 https://blog.ghost.org/2-0/
It is a huge update with new Koenig Editor with focus on writing. Here's how to update ghost to version 2.0.
First, update your Ghost-Cli to the latest version.
sudo npm install -g ghost-cli@latest
Second, install the latest version of Ghost 1.0
ghost update --v1
Last, run the update command as usual
Check the version