In December 2023 we launched a new layout. So that we could get feedback and make the transition smooth for people we decided to keep the existing (Classic) layout available for people temporarily.
In 2024 we will phase out the classic layout and move all accounts and people to the new layout. But until we do that, both layouts will be available to use.
To switch from the classic layout to the new layout click on the "Options" button on the welcome page and click "Switch to new layout":
To switch from the new layout to the classic layout click your name and profile image at the bottom of the sidebar and click on "Switch to classic layout":