As a result, users will no longer be able to create new accounts or re-verify existing accounts on these devices.
The move will eventually lead to the messenger crashing and becoming unusable, after update support is withdrawn on New Year's Day.
Specifically, it's ending support for BlackBerry OS (including BlackBerry 10) and Windows Phone 8.0 and older on December 31st. A while back the company also stopped supporting the Symbian operating system which was once the pride of Finnish phone maker Nokia.
If you're still using WhatsApp on a BlackBerry or Windows Phone 8.0 or older then you might want to consider making the switch to Android or iOS in the near future, because the app is no longer going to be actively developed for those less popular platforms.
The next step in slimming down the platforms that WhatsApp is offered on will be the cut-off of the Nokia S40 on December 31, 2018.
The messaging app, which launched in 2009, has more than one billion users. Blackberry 10 was its ambitious replacement which failed to give iOS and Android a run for its money and was eventually forgotten by Blackberry themselves.
After January 1 you will not be able to access WhatsApp on your mobile phone if it happens to be of certain models.
'If you use one of these affected mobile devices, we recommend upgrading.
'Keep in mind that WhatsApp can only be activated with one phone number on one device at a time.
It also said there was now no option to transfer people's chat history between platforms. However, we provide the option to send your chat history attached to an email.
The above mentioned operating systems are now being used by a handful of users, and have aged since.
The platforms that are being cut are unpopular, and have been for some time. "About 70 percent of smartphones sold at the time had operating systems offered by BlackBerry and Nokia", it reads.
Only devices which still operate Windows Phone 8.0 or earlier will be affected. If you have been looking for a good reason to jump ship to a different mobile OS, you've just been given another reason to do so.