Update: This issue appears to be resolved and notifications for WhatsApp are slowly coming back online for Windows Phone 8.1 and Windows 10 Mobile handsets. Original article follows.
If you've been wondering why nobody has messaged you on WhatsApp this morning, they probably already have and you just didn't know. It appears WhatsApp on Windows Phone is suffering from an issue that has stopped all notifications coming in until you open the app, essentially making the platform useless for Windows Phone users on Windows Phone 8.1 and Windows 10 Mobile.
It's unclear what's caused the issue, but the issue itself appears to be widespread on both the production WhatsApp and WhatsApp Beta apps, making us believe it may be a server issue. It's also unclear if this is a global issue or regional one. Sending a message to someone using WhatsApp on Windows Phone right now will see that message not get delivered until they open the app, which is why Windows Phone users aren't receiving notifications.
Windows Central has been able to confirm that notifications are not working on Windows 10 Mobile using both WhatsApp and WhatsApp Beta apps in the UK, on both the Anniversary Update and Creators Update. Reinstalling the app does not appear to fix the issue. We've reached out to WhatsApp for comment, and will update this article when we know more or if the issue gets mended. In the meantime, are you still receiving notifications from WhatsApp on Windows Phone?