I have determined that the crash occurs when Viber tries to look for fresh update on download.cdn.viber.com
So solution that works is to prohibit any Viber connection to this server. I did it with littlesnitch rule.
If you'r not using littlesnitch then you can do it with hosts file:
- Open your terminal
- Type in sudo nano /private/etc/hosts and then your admin password
- File will open. Go to the last line and type 127.0.0.1 download.cdn.viber.com
- Press Ctrl+O (save file) and Ctrl+X (close file)
Now Viber should work without any crashes but youll have to install updates manually