From the announcement on Medium:
Today, we are sharing the news that in the coming months we’ll be discontinuing the mobile app.
Nothing is happening to the apps, website or your Vines today. We value you, your Vines, and are going to do this the right way. You’ll be able to access and download your Vines. We’ll be keeping the website online because we think it’s important to still be able to watch all the incredible Vines that have been made. You will be notified before we make any changes to the app or website.
This was published earlier today, likely in an effort to hide it within the noise of the Apple event.
Vine founder Rus Yusupov tweeted the following shortly after the announcement:
Don’t sell your company!