From the PayPal blog:

For Windows Phone users, we will sunset the current version of the PayPal app on June 30. However, Windows Phone users can still access PayPal through our mobile web experience on Internet Explorer and Microsoft Edge browsers. Outlook.com users can also use the PayPal add-in to send money directly from their inbox.

If you are an Amazon Fire or Blackberry user, we will be discontinuing the PayPal app on June 30, after which you will no longer be able to use the app. However, customers on these devices can still log into PayPal on these phones via our mobile web experience. Blackberry users can also continue to use the BBM app to send peer-to-peer payments via PayPal.

That leaves iOS and Android. Not a death blow to Windows Phone, Amazon Fire, or BlackBerry, but a recognition of reality, that the revenue from those platforms no longer justify the cost of supporting them.