Twitter recently provided an update to the web view so that depending on which of its two feeds you were viewing last, it will load it when you return to the site by default. This new update has come to both the iOS and Android apps and is rolling out now.
This is live for Android and iOS!
— Twitter Support (@TwitterSupport) February 6, 2023
Update to the latest version of the app so that “For you” and “Following” will default to whichever tab you had open last. https://t.co/GB1TxWJoOm
These two timelines, the newer "For You" feed which is the curated feed, and the "Following" feed which is the traditional chronological feed, replaced the previous Home and Latest feeds that were selected with the star icon in the top corner of the app.
When they first rolled out, whenever the Twitter app was closed it would re-launch with the For You tab visible first by default. This prompted many complaints from users who prefered the more traditional chronological feed.
This change comes amidst a raft of new features and changes being made on the platform since Elon Musk took over, with most drawing ire from its users causing them to migrate to rival platforms.
Source: Twitter