You can check for an update through the Google Play Store.
- Launch the Google Play Store on your phone: https://play.google.com.
- Choose the menu
button at the top left - Choose "My Apps and Games"
- Find and select "Lookout Security & Antivirus"
- If the "Update" button appears then you will know that there are updates available. Click on it and the app will update.
Note: If you want to set your device to automatically update your Lookout app, choose the menu 
button at the top right of our store page then check the box for "Auto-update."