V 15.6.0
Viber for Mac is synced to your mobile account.

V 15.6.0.3
Viber for Desktop is synced to your mobile account.

V 1.0.9002
where you can belong to a school club, a gaming group, or a worldwide art community

V 5.7.0
Video calls and meetings with tons of other possibilities

V 7.0.4
ooVoo is a free instant messaging and video call app