Viber's new privacy-enhanced version includes:
Increased security - the padlock icon confirms that all your messages - including groups and cross platform messages - are end-to-end encrypted
Hidden Chats - hide away specific chats so nobody knows they even exist
Contact authentication - a new layer of security allows you to protect yourself further with a simple 'trust contact' mechanic
'Like' media from the preview screen - click the heart to like photos and videos even while you're watching them.