Twitter is working on a way to receive notifications about new tweets that match a specific search term in the latest pre-release version of the mobile app.
The official Twitter app has always been the best app for tweet-related mobile notifications, albeit limited to only new tweets from accounts you follow. Meanwhile, TweetDeck on the desktop provides an expanded suite of notification options while maintaining the speed of an official Twitter application.
According to Android developer and 9to5Google contributor Dylan Roussel, when users search on Twitter, they notice a bell icon next to the search bar. When users tap it, they’ll be told that "you're subscribed to receive push notifications for Tweets about" whatever you searched for. Based on the two preview screenshots, this appears to be similar to TweetDeck's ability to enable notifications for any given column.
Search Subscribe appears likely to become a new component of the paid Twitter Blue subscription, given the recent trend of exciting new Twitter features debuting as premium exclusives.