Just as a reminder, this includes WhatsApp for users on either BB10 or Windows Phone 8 handsets. Last year WhatsApp announced that they would be ending support for those platforms in the middle of 2017, but they later had a change of heart when they decided to extend support until end of the year.
However it looks like there will be no more extensions as support will officially end in the next few days, as noted on WhatsApp’s blog. It is actually interesting that WhatsApp will be ending their support when BlackBerry themselves have recently announced that they will be extending support for BB10 for an additional two years.
Then again we can imagine that the number of users on BB10 and Windows Phone 8 is probably too low for WhatsApp to commit their resources to either platform, at least based on the current state of things.