Unfortunately, due to necessary updates in the SDK we target, we had to drop support for Android 4.4. The minimum Android requirement as of QField 1.0 RC 3 is Android 5.0 (SDK version 21).
In case playstore does not suggest an update to QField Lucendro 0.11.90, the last working version for Android 4.4, we suggest all Android 4.4 users to uninstall QField 1.0 RC 1 (which was broken on android 4.4) and reinstall QField from the store.
If you do not use playstore, install this version