@JehadJawad-1864,
This upgrade notification is received because Skype for Business Online customers that are scheduled for assisted upgrades to Teams. For more information, please refer to the Notifications for scheduled customers part in this article.
It is known to all that Skype for Business Online is retired on July 31, 2021. Then, it should be upgraded to Microsoft Teams, which contains and extends the capabilities of Skype for Business Online. If your organization doesn’t finish the upgrade prior to the retirement date, Microsoft will provide an assisted upgrade process to help you move any remaining Skype for Business Online users to Teams Only. For more details, please pay attention to the What this means for Skype for Business customers section in this document.
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