
WhatsApp will begin removing support for other Android, iOS and KaiOS devices running older OS versions from 1 Nov 2021.
WhatsApp is constantly updating its app on each operating system to improve security and feature listing as well. The minimum requirements for computer hardware are growing to take advantage of new features. Older smartphones will no longer be eligible to use the Meta-owned messaging system.WhatsApp will start removing support for other Android, iOS and KaiOS devices running older OS versions from 1 Nov 2021.
To continue using the app, the user will have no choice but to get a new device with app support. Users can back up their chat history before moving to a new device to save all conversations and media.

Android
Devices running on Android 4.0.4 and older versions will stop supporting the messaging app. The Ice cream Sandwich update was released in 2011.
Other popular Android devices that will not be able to use WhatsApp include Samsung Galaxy SII, Galaxy S3 mini, Optimus L5 Dual, Optimus L4 II Dual, Optimus F7, Optimus F5 and more.
The list of Android phones released by WhatsApp includes smartphones from Samsung, LG, ZTE, Huawei, Sony, Alcatel, and others.
iOS
The minimum requirement to use WhatsApp will be limited to iOS 10 and newer versions. Any iPhone running on OS older than iOS 10 will not work from November 1st. Devices like the iPhone 6S, iPhone 6S Plus, Apple iPhone SE (first generation) will stop supporting the messaging system.
KaiOS
WhatsApp only supports phones running on KaiOS 2.5.0 and later. Both the JioPhone and JioPhone 2 will continue to receive support.
While switching to new devices, users are advised to back up their conversations and other data in order to continue using the app with minimal disruption.