MC249395 – This message post is a reminder of the ongoing progress of retiring TLS 1.0 and TLS 1.1 protocols in Microsoft 365.
As previously communicated (MC126199 in Dec 2017, MC128929 in Feb 2018, MC186827 in July 2019, MC218794 in July 2020 and MC240160 in February 2021), Microsoft is moving all our online services to Transport Layer Security (TLS) 1.2+ to provide best in class encryption, and to ensure our services is more secure by default. The changes to enforce TLS1.2+ in our service started on October 15, 2020 and will continue to propagate through all Microsoft 365 environments for the next few months. If you have not taken steps to prepare for this change, your connectivity to Microsoft 365 might be impacted.
Yammer recently made a change to a certificate to ensure Microsoft supports default ciphers. To view which ciphers www.yammer.com supports, please visit SSL Report
How this affects your organization:
Any applications that call Microsoft 365 APIs over TLS 1.0 or TLS 1.1 will need to be updated to use TLS 1.2. The .NET 4.5 framework defaults to TLS 1.1.
What you can do to prepare:
For information on updating the .NET configuration, please visit How to enable TLS 1.2 on clients
For information regarding the deprecation of TLS 1.0 and 1.1 in Office 365, which includes Yammer, please visit Preparing for TLS 1.2 in Office 365 and Office 365 GCC