On iPhone (iOS):
Open the App Store from your mobile device.
Click on your profile icon at the top of the screen.
Scroll to see pending updates and release notes.
Click "Update" next to the Pleo app.
On Android:
Open the Google Play Store app.
At the top right, click the profile icon.
Click "Manage apps & device".
The Pleo app will be flagged with an "Update available" label.
Click Update.