This is a pretty serious issue because it impacts security as well as other functions. Back in September, Microsoft noted that some older versions of the app will lose connectivity to Microsoft 365 services. So for Office 20, you can only upgrade to the above Microsoft Office versions or to Office 2019 to continue using Office 365/Microsoft 365 services from Outlook.If you’ve been using an older version of Microsoft Outlook, then it may not be functioning any longer. 1000 of Office 2013 (Service Pack 1 with the October 2017 update) In general, Microsoft is encouraging users to upgrade to the following versions: These users should be moved to newer, supported versions. Microsoft's customer support team is therefore actively reaching out to the tenants that use Outlook 20 the most. Microsoft is aware that some customers can't just not give up the old Outlook versions. On the service side, Microsoft will be able to better prioritize requests and deliver data to clients more effectively.īased on usage data, Microsoft could see that the number of old Outlook versions in requests has dropped sharply. HTTP/2 is a full-duplex protocol that reduces latency through header compression and request multiplexing. Microsoft is working to add support for HTTP/2 in Microsoft 365.To increase the security of Microsoft 365, modern authentication protocols will be used. Support for Basic Authentication will end (see also my post Disabling Exchange Online Basic Authentication in 2021).Older versions of Outlook such as Outlook 20 are not compatible with the following upcoming service changes, and will therefore be blocked.

This will require some changes, which will cause problems with older Outlook features. The reason for this exclusion is that Microsoft wants to make communication more secure. 1000 werden dann nicht mehr unterstützt und können nicht mehr auf die Dienste zugreifen. Outlook 2007, 2010 und Office 2013-Versionen vor.After November 1, 2021, only Outlook 2013 Service Pack 1 (with the latest fixes) and higher will be able to connect to Microsoft 365 services.Microsoft reminds users that it's not far off until November 1, when the minimum version requirements for connecting Outlook for Windows to Office 365/Microsoft 365 services will change. It was announced on Augin the New minimum Outlook for Windows version requirements for Microsoft 365.

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