title: What is the difference between Expo CLI and Expo SDK
body: <p>I am working on expo project by following online tutorials. I used <strong>npm install -g expo-cli</strong> to install the CLI. I also used <strong>expo init AwesomeProject</strong> to initialize a new expo project. Later i came to know that there is something called <strong>expo SDK</strong> and the latest version as of today is 42. So, i decided to check mine using <strong>expo --version</strong>. I got 4.3.2 as result and i can upgrade it to 4.9.1 by running <strong>npm install -g expo-cli</strong>. I realized that it is nothing do to with SDK version. Now i am confused with expo CLI and SDK because the tutorial doesn't even tell anything about SDK. Is it important to know about expo SDK ? and what's the difference between expo CLI and expo SDK and how to check its version? Thanks.</p>