Microsoft Teams vs Classic Teams
Microsoft has redesigned the Teams App to prioritize speed, performance, and flexibility. Some of the changes you will notice:
Increased Speed- Up to two times faster when launching the app, joining meetings, and switching chats and channels.
Less space - Teams uses less processing power to increase performance and prolong battery life
Improved Collaboration - Easily collaborate with colleagues using Teams at other organizations.
Once Teams upgrades on your device, you can switch between the new Teams and Classic Teams by clicking the toggle button in the upper left corner of the app:
If you are using the Saved feature in Classic Teams, this feature is not yet available in the new version of Teams. To view your Saved messages, you can switch to Classic Teams and still use the feature.
To learn more about new Teams, please see this article from Microsoft.