Messaging service WhatsApp will stop working on more than 50 phone models from next week.
From Monday, November 1, some 53 devices have stopped supporting the app and users are advised to check in whether they will be affected.
People impacted by the changes will see WhatsApp suddenly blocked from working on their phones.
However, affected phone owners still have time to avoid being shut out of the service if they make certain updates before the changes kick in.
Both Android and iPhone models will be hit by the blockage, with users required to update their operating systems if they have not done so already.
Apple devices need to be running iOS 10 upwards, while Android users will need to be on Android 4.1 or later in order for WhatsApp to still be compatible.
Users can find out what version of the operating system they are currently running on by visiting the settings section on their phones.
The Samsung devices set to no longer compatible with WhatsApp are: Galaxy Trend Lite, Galaxy Trend II, Galaxy SII, Galaxy S3, mini Galaxy Xcover 2, Galaxy Core and Galaxy Ace 2.
From November 1, the app will have stopped working on the following LG devices: Lucid 2, Optimus F7, Optimus F5, Optimus L3 II, Dual Optimus L5, Best L5 II, Optimus L5, Dual Best L3 II, Optimus L7, Optimus L7, Dual Best L7 II, Optimus F6, Enact Optimus F3, Best L4 II, Best L2 II, Optimus Nitro HD, Optimus 4X HD and Optimus F3Q.
Huawei smartphone users will need to install upgrades if they use the following devices: Ascend G740, Ascend Mate, Ascend D Quad XL, Ascend D1 Quad XL, Ascend P1 S, and Ascend D2.
The other phones impacted are: ZTE V956 Grand X Quad V987 and Grand Memo, Alcatel, Archos 53 Platinum, HTC Desire 500, Caterpillar Cat B15, Wiko Cink Five, and Wiko Darknight, Lenovo A820 UMi X2, Run F1, THL W8.