Last year, we announced some forthcoming changes to make Tweets more flexible, by not counting @replies and certain categories of link attachments in the 140 characters of a status update.
This was a staged rollout, and the
attachment_url change has been available for several months already.
Today, we've shipped the simplified replies experience on Twitter.com, on our mobile clients, and on TweetDeck.
For the sake of completeness, please note that the technical documentation on the change is available at this single page. We've also just shipped final updated Display Requirements which all apps and sites should follow.
Due to the number of Twitter API endpoints affected by this change, we will be socialising the updated parameters across the rest of the documentation over the coming months. Note that developers should use the
?tweet_mode=extended parameter on any endpoint that returns Tweet objects in order to see the full new format. See the technical documentation for further clarifications.