WhatsApp alerts not working after iOS10 update

I upgraded to iOS10 yesterday night and since the update my custom alerts in WhatsApp are no longer working. No matter what sound I set the alert to, I only get a default, generic sound when I receive any message.

Does anyone know if this can be fixed by user intervention, or does it require an app update which WhatsApp will have to produce in the next few days?

Using iPhone 6/16 Gb - WhatsApp v2.16.10 - iOS 10.0.1