The update, now waiting for you inside BlackBerry World, brings what is being called a "dark theme" to those with a device running BlackBerry 10.2.1. Other new features include privacy settings for last seen, status and profile picture; additional multi-select options on the chats list, additional options for clearing and deleting conversations; an updated appearance for the chat bubble, bug fixes and the addition of support for the Russian language.
It is interesting how BlackBerry considers the use of PINs instead of usernames to be a positive for BBM users, while WhatsApp decries the use of PINs and says that its use of phone numbers makes it easier to use. BlackBerry touts PINs as a more secure way to get in touch with a fellow BBM subscriber.
WhatsApp is a free download for BlackBerry 10 users, although there is a 99 cent annual charge for its use after the first year.
source: WhatsApp via Crackberry