Deleting messages without leaving a "deleted message" notification.
Using a modded APK instead of the official version from the Google Play Store or official Viber site carries heavy risks: Rakuten Viber Messenger 18.9.2.0 (nodpi) (Android 5.0+) Download Viber v18 Extra Mod apk
While there is no official "Extra Mod" for Viber from Rakuten Viber , third-party modded APKs like "Viber v18 Extra Mod" are often advertised to unlock premium Viber Plus features for free. Claimed Features of "Extra" Mods Download Viber v18 Extra Mod apk