If they seem to be doing something that is "more or less" the same then my radar is triggered for them not actually declaring they are delivering totally encrypted (ie no backdoor tomfoolery) voice calls.
Over the past year, we've been progressively rolling out Signal Protocol support for all WhatsApp communication across all WhatsApp clients. This includes chats, group chats, attachments, voice notes, and voice calls across Android, iPhone, Windows Phone, Nokia S40, Nokia S60, Blackberry, and BB10.
Are you saying "maybe/maybe not"?
If they seem to be doing something that is "more or less" the same then my radar is triggered for them not actually declaring they are delivering totally encrypted (ie no backdoor tomfoolery) voice calls.