Use APKPure App
Get Days Until old version APK for Android
Simple design
Countdown the days until the date and time you choose!
Available in 100+ languages.
Code is opensource: https://github.com/amandaroos/DaysUntilAppFree
Widget is available in the upgrade version: https://play.google.com/store/apps/details?id=com.amandaroos.daysuntilapp