WhatsApp will stop working on any version of Windows Phone/Windows 10 Mobile operating systems after December 31, 2019. This is the last date officially informed by WhatsApp to support “Windows Phone operating systems”.

As noted in the official FAQ,

Note: WhatsApp will no longer support Windows Phone operating systems after December 31, 2019, and the app might not be available on the Microsoft Store after July 1, 2019. Because we no longer actively develop for these operating systems, some features might stop functioning at any time.

In case you want to save the chat history, you can do so for the individual chats.

To export your chats

If you would like to keep a record of your messages on a computer or in an email, you can email yourself individual chats. Please follow these steps:

  1. Open the chat you wish to export.

  2. Tap on More > info or group info.

  3. Tap on More > email chat history.