On 5 April, WhatsApp users may have noticed a strange yellow message creep into their usual stream of Emoji and 'we-just-met-on-Tinder' chat.
There's no cause for alarm - as anyone who clicked the message will have found out, WhatsApp has updated its security features to incorporate "full end-to-end encryption" of messages, calls and file transfers you carry out on the messaging service.
By updating to the latest version of the app, users are now guaranteed that no one else can access your conversations other than the intended recipient."Not cybercriminals. Not hackers. Not oppressive regimes", says Whatsapp. Not even they can access your messages.
"Your messages are secured with a lock," explains the Facebook-owned app, "and only the recipient and you have the special key needed to unlock and read them. For added protection, every message you send has its own unique lock and key. All of this happens automatically: no need to turn on settings or set up special secret chats to secure your messages."
You can read more about the new system, developed with Open Whisper Systems, right here.
The move will be welcomed by many security advocates: following the lengthy FBI vs Apple court case in the US, the right to user privacy has been debated by major government and technology groups.
However, with WhatsApp effectively guaranteeing that it can't access messages sent by its own service, it puts groups like Apple in an increasingly frustrated position. Say another government group, such as the FBI, obtains a phone that it believes has been used by a terrorist to organise an attack. They can't turn to WhatsApp for help accessing the individual's messages, as WhatsApp has declared it can't get at them - it's impossible thanks to this encryption system. The only option would be to unlock the physical phone itself to view the messages stored on it - and we've just seen how that played out.
Expect the debate of 'Privacy v Public Security' to rage on into the future.