Viber introduced group calling with version 10 in February 2019.
Currently Viber group call can have a maximum of up to 20 people. You can make group calls only in voice calls, not video calls.
How to make a group call
Please note: Users need Viber version 10 or newer to use group call feature.
Group calls can be made in many ways
1) If a group is already created in Viber, group call can be made from inside a group chat
In a group of up to 20 people, tap the phone icon at the top of the group to start a call with all members of the group. If the group has more than 20 people, then the phone icon is not available to make group call.
2) If a group call is in progress with less than 20 users, you can add a new user from the contacts by tapping the Add to call button to the call, from inside a call. Adding a new user to a group call will not add them to a group chat.
3) Join a group call when another user invites you - a banner will appear on your screen notifying you about the call. You can join the call by tapping ‘Join Now’. As long the call is in progress, The banner will appear on your screen, so you can join at any time.
You can also make or join a group call on your computer with Viber for Desktop.
How to find a past group call in Viber?
If you would have been part of any group call that took place in the past, it will appear in your chats list. You can tap the phone button to start a new call with the members of this call.