Twitter Direct Messages have never been my preferred messaging platform, but for those who do use it, there are a few new features —read receipts, typing indicators, and web link previews. If you use other services such as Facebook Messenger, Hangouts, Telegram, and WhatsApp, you've probably already seen these.
Read receipts are those little indicators that show the sender their messages have been read by the receiver. All of the previously mentioned services utilize these, but many users hate them with a passion. If you're one of those, don't worry; the read receipts can be disabled through Twitter's security settings. However, if you do so, you won't be able to see if other people have read the messages you've sent to them. Currently, this feature is only available in Twitter's Android and iOS applications, but it should be on the web shortly.
The new features that Twitter is revealing alongside read receipts are typing indicators and web link previews. Typing indicators are pretty straightforward; they show when someone is typing a message to you. Web link previews are also self-explanatory; they show short previews of links that people send in messages. The aforementioned competing platforms have both of these features in some capacity.
All in all, these are some solid changes. No app update is needed to take advantage of these features, and they're available right now.