The expectation is that WhatsApp for Windows Phone users will get the feature on an invite-only basis, just as WhatsApp voice calling feature was rolled out on Android. This will subsequently extend across the entire Windows Phone community and sooner or later come into view on all devices making use of Windows Phone.
In view of the fact that there is little to corroborate in this news, it is pretty promising to see a different scheme by the time Windows Phone update is being rolled out, particularly when this group is not that large.
Download WhatsApp for Windows Phone here.