WhatsApp is one of the most popular messaging apps in the world, but soon it’ll stop working for users on some Older mobile operating systems.

According to a support document, WhatsApp will stop working for all Windows Phone devices after December 31, 2019. That’s tomorrow, so if you’re still rocking a Windows Phone device, you may want to begin looking into a new phone or a new messaging service.

Then on February 1, 2020, WhatsApp will stop working on select older Android and iOS versions. That includes Android 2.3.7 and older as well as iOS 8 and older.

WhatsApp says that after those dates, you’ll no longer be able to create new accounts nor reverify existing accounts. The company also says that because those older Ones are no longer being developed for, you might see some features stop working at any time.

It’s never good to see a major service like WhatsApp drop support for devices, but these OSes are several years old and it’s difficult to continue supporting such old versions, especially as their usage numbers dwindle over time. If you’re on an older OS, you can backup your chat history for when you move to a new phone on the same platform, so that’s something to consider if you’re on an older OS that’s losing support for WhatsApp.