WhatsApp is cracking down on third-party app WhatsApp Plus, and punishing users who downloaded it.
The Facebook-owned company has cut off access to the unauthorized WhatsApp Plus service, which provided additional customization for the popular SMS service.
"The developers of WhatsApp Plus have no relationship to WhatsApp, and we do not support WhatsApp Plus," WhatsApp said on its FAQ page.
"Please be aware that WhatsApp Plus contains source code which WhatsApp cannot guarantee as safe, and that your private information is potentially being passed to [third] parties without your knowledge or authorization," the company said.
"We have received a cease-and-desist letter from WhatsApp and we are obligated to remove all download links," WhatsApp Plus creator Mounib Al Rifai wrote in a Google+ post.
"Am really sorry for this but it's out of our hands and WhatsApp has pushed us into a corner that we can't escape this time," he added.
According to the BBC, folks were required to uninstall WhatsApp before gaining access to Plus features like increased attachment size limits and additional anonymity.
But WhatsApp Plus users who are now attempting to return to the official WhatsApp application are being locked out for 24 hours for breaking the rules.
Meh! Banned from whatsapp because of using WhatsAppPlus. They really want those blue ticks to prosper. #FreeWhatsapp+ pic.twitter.com/J3h7ISnV1U
— Carpe Diem (@MyTenacious) January 20, 2015So whatsapp just temporarily banned me. Smh pic.twitter.com/QBHMQLEKhm
— Doc Shebeleza (@Gichana_) January 20, 2015Just got banned on WhatsApp. #whatsapp #whatsappplus #whatsapp+ pic.twitter.com/tjsslXdea6
— Pratik Gole (@PratikSGole) January 20, 2015WhatsApp declined to comment on the issue, instead providing PCMag with the same statement posted to its FAQ page.
"After the 24-hour countdown ends, you will be able to use WhatsApp," the email added.
The crackdown comes almost a year after Facebook acquired the messaging application for $16 billion. Earlier this month, WhatsApp announced a milestone 700 million monthly active users. Gaining 200 million subscribers in less than a year, the service appears to be on track to surpass 1 billion by 2017.
For more, see PCMag's review of WhatsApp Messenger for Android and iOS and the slideshow above. Also check out What Is WhatsApp? An Explainer.