Expanding the App Push Notification (APN) received on a device is called as Big Text feature.
If you are unable to receive to expand the APN received, this will be due to the below reason :
1. SDK version integrated with your App is older than 2.0.10 on Android and 2.2.11 on Android X.
All SDK's versions greater than 2.0.10 in Android and 2.2.11 on Android X support Big Text feature. It is necessary you update your App with Smartech's latest SDK to avail the Big Text feature and many other features.