The minimum supported version of the viva.com terminal is the 4.8.0.
This means that your device* will be unable to accept payments unless you update the viva.com terminal to the latest version.
Steps to update viva.com terminal
Open Google Play / App Store
Search for "viva.com terminal"
Tap on the "Update" button
*Smartphones and tablets running viva.com terminal
Ciontek CS30PRO
Ciontek CS30PRO with professional scanner
Ciontek CS50C
Mini Card Reader connected to Android devices via Bluetooth or USB