Messaging app WhatsApp will stop working on thousands of phones from today (1 November).
Some 43 different phone models will be affected as the Facebook-owned app changes its requirements for Android and iOS operating systems.
The WhatsApp FAQ section has encouraged people to use Android version OS 4.1 or iPhone 10 and newer to keep the app working.
Which phones are impacted?
The iPhone SE (2016), 6S and 6S Plus will be affected as the models launched with iOS 9. However, the models can be updated to iOS 15 in order for WhatsApp to work.
Older models of iPhones that cannot be updated past iOS 10, such as the iPhone 4S from 2011, will lose access.
The Samsung Galaxy Trend Lite, Galaxy Trend II, Galaxy SII, Galaxy S3 mini, Galaxy Xcover 2, Galaxy Core and Galaxy Ace 2 will all be affected.
The LG Lucid 2, Optimus F7, Optimus F5, Optimus L3 II Dual, Optimus F5, Optimus L5, Optimus L5 II, Optimus L5 Dual, Optimus L3 II, Optimus L7, Optimus L7 II Dual, Optimus L7 II, Optimus F6, Enact , Optimus L4 II Dual, Optimus F3, Optimus L4 II, Optimus L2 II, Optimus Nitro HD and 4X HD, and Optimus F3Q.
The ZTE Grand S Flex, ZTE V956, Grand X Quad V987 and Grand Memo.
The Huawei Ascend G740, Ascend Mate, Ascend D Quad XL, Ascend D1 Quad XL, Ascend P1 S, and Ascend D2.
The Sony Xperia Miro, Sony Xperia Neo L, Xperia Arc S.
The Alcatel One Touch Evo 7, Archos 53 Platinum, HTC Desire 500, Caterpillar Cat B15, Wiko Cink Five, Wiko Darknight, Lenovo A820, UMi X2, Faea F1 and THL W8.
What if my phone is too old?
The app may not stop working completely on the old phone models however it does mean you will not be able to download updates which could cause crashes, bugs or security issues in some cases.
You will need to pay to upgrade your phone in order to keep access to WhatsApp.
However, there is a way to save your chat history from the app if you want this saved before you upgrade.
You can back up your message history to Google Drive or iCloud depending on whether you are an iOS or Android user.
Alternatively, you can export your chat history as an email attachment.
What are the new WhatsApp features?
Those with newer phone models and upgraded devices will be able to access the app’s latest features including disappearing messages.
This was introduced in November letting users send vanishing messages in separate conversations as well as group chats.
Another recently added feature includes the option to quickly join an ongoing group audio or video call.
A version of this article originally appeared on NationalWorld.com