We have had readers asking if WhatsApp also added voice messages for the Legacy BlackBerry Java devices together with BlackBerry 10 devices. I am happy to confirm that both BB10 and legacy devices got the feature added. It can take up to a day or so for the feature to show up due to the client needing to pick up the server change. Using the voice message feature on legacy devices is also a bit more subtle. You either hold down the spacebar on QWERTY devices or hold down the text input box on full touch devices. This is a little different than the holding down of the microphone icon on BlackBerry 10.
Check out the full details in the FAQ for the WhatsApp BlackBerry client