WhatsApp has detailed its plans for older mobile operating systems, with less than a week before the end of the year. The Facebook-owned app will end support for BlackBerry OS (including BlackBerry 10) and Windows Phone 8.0 (and older) on December 31, 2017.

The end of support doesn’t mean WhatsApp will no longer function on these platforms. That said, you will no longer be able to create new accounts or re-verify existing accounts. Furthermore, WhatsApp warns: “Because we will no longer actively develop for these platforms, some features may stop functioning at any time.”

WhatsApp offers the following advice for owners of these older devices:

These platforms don’t offer the kind of capabilities we need to expand our app’s features in the future. If you use one of these affected mobile devices, we recommend upgrading to a newer OS version, or to a newer Android running OS 4.0+, iPhone running iOS 7+, or Windows Phone 8.1+ so that you can continue using WhatsApp.

Once you have one of these devices, simply install WhatsApp and verify your phone number on the new device. Keep in mind that WhatsApp can only be activated with one phone number on one device at a time.

There is currently no option to transfer your chat history between platforms. However, we provide the option to send your chat history attached to an email. Learn how to export your chat history on: Android | iPhone | Windows Phone | Nokia S40 | BlackBerry | BlackBerry 10

If you’re a BlackBerry user and want to keep getting WhatsApp updates, you’ll need to switch to an Android-powered BlackBerry device. Earlier this month, BlackBerry shared that BB10 will be supported for “at least two” more years.

If you’re a Windows Phone user, you should still get WhatsApp updates on Windows 10 Mobile devices. That said, given that Windows 10 Mobile is dead, this is as good a time as any to switch to Android or iOS.

WhatsApp announced a similar move at the end of 2016, ending support for older mobile operating systems including from BlackBerry and Nokia. In fact, BlackBerry 10 was supposed to be on the cutting block, but WhatsApp kept support around for another year.

As for Nokia, WhatsApp has also shared that support for the Nokia S40 will be dropped on December 31, 2018. Older Android devices (version 2.3.7 and older) have the longest timeline: They will be supported until February 1, 2020.