Millions of smartphone users won’t be able to access WhatsApp on their devices from January 1 2021. It’s confirmed by WhatsApp official FAQ page because WhatsApp Stop Working on these Phones from Jan 1 2021 on List of Smartphones (Why?).
WhatsApp has always been supportive to provide new updates and features to its users but this time they are taking it back. Dropping support for older devices has always been a regular job for WhatsApp for the older version which are near to expire. This time it’s no different as some devices will still be able to access WhatsApp by updating to their latest android/iOS versions, However, for some, it won’t be accessible from January 2021 as WhatsApp will stop working on list of phones from 2021.
WhatsApp Stop Working on these Phones from Jan 1 2021- List of all Smartphones & OS
According to the announcement, WhatsApp will stop working on these devices as Devices running below Android 4.0.3 or iOS 9 Devices and running Kai OS 2.5.1 including JIO phone and JIO phone will not be able to access WhatsApp starting Jan 1st until users can update to latest firm update because there is no other option.
List of OS on which WhatsApp stop support from 2021-

iOS– It means either you have to update your phone to the latest software version or you may not be able to use WhatsApp on your devices and Coming to iOS, iPhone 6s and above supports iOS 14. iPhone 4 doesn’t support more than iOS 7. So iPhone 4s, 5, 5s, 6 and 6s users will need to update their devices to iOS 9 to continue using WhatsApp.
Android– As for android smartphones running older than android 4.0.3 Ice Cream Sandwich like HTC Desire, LG Optimus L7 etc , WhatsApp won’t work anymore. Most of the older devices aren’t available anymore for sale so it won’t be an issue for new buyers. The upgradable phones will have access if those are updated to Android 4.0.3 or above.
Windows– If you own a Windows Phone device of any sort, your last day for WhatsApp was all the way back on January 1, 2020. That included every single mobile device that runs Windows Phone OS, or any predecessor of that operating system. All your old Nokia Lumia devices where and remain entirely WhatsApp-dead- SlashGear
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To check if your phone is running on the latest version of Android, do a manual check by going into the Settings menu. Select About Phone from the list of options and tap on Check for Updates. The phone will perform a check for any pending OTA update for your smartphone.
What can you do at last?
If nothing works out then the last resort you have is to update to a new device or throw it out of the window because the company won’t push any update or support even if you manage to root or do some black magic. “Furthermore, WhatsApp also said that there’s no option to transfer your chat history between platforms. However, it provides the option to export your chat history as an email attachment.”- Livemint