Popular iPhone and iPad Twitter app Twitterrific has been updated to take advantage of some high profile iOS 13 and iPadOS features. Multi-window support, Dark Mode, and other improvements are part of the Twitterrific 6.1 update.
It seems that Twitter is experiencing a patchy outage across many of its services. Twitter has itself tweeted to confirm it is investigating outages for Twitter and TweetDeck. There also seem to be issues tweeting from Twitter for iOS.