Facebook integration is also a casualty of this change as TweetDeck will live on as a browser based application. A dedicated Chrome app is being developed as well.
After Twitter purchased TweetDeck a couple years ago, the company has made huge advances in its native iOS, Android and Windows Phone apps. TweetDeck, which relied on Twitter's version 1.0 API was in the way.
TweetDeck announced today that May 7th will be the official date for the applications getting pulled from their respective stores and that the apps would also no longer function. If you are a power user who longs for Facebook integration, a viable alternative is HootSuite which is available for iOS and Android.
There are also other third-party Twitter apps like Tweetbot for iOS or Plume for Android. However, if you have not looked at the native Twitter apps for either platform in a while, it might be worth checking out as the apps have made some solid advances in the past several months.