Automatically switch to the new Stream (on SharePoint) when recommended: This is the default option. At this time, this option directs the Stream tile to Stream (Classic).You will be able to set the target destination to either Stream (Classic) or Stream (on SharePoint) depending on your organization’s needs. SharePoint tenant admins will have the ability to set the target destination of the existing Stream tile in the Microsoft 365 app launcher from the SharePoint Admin Center. Standard: will begin rolling out in early July and expect to complete by late August. Targeted release (entire org): will begin rolling out in late May and expect to complete by late June. This message is associated with Microsoft 365 Roadmap ID 88823 Do this by configuring the target destination of the existing Stream tile in the Microsoft 365 app launcher from the SharePoint Admin Center. Until Stream (Classic) fully retires, you can decide which Stream experience is most appropriate for your users on.

Stream (Classic) is transitioning to Stream (on SharePoint).

Customize app launcher office 365