Microsoft statement – December 21, 2018

We’re retiring 3DES in Office 365 beginning February 28, 2019

Major update: General Availability rollout started
Applied to: All customers

 

As previously communicated (MC124104 in October 2017, MC126199 in December 2017 and MC128929 in February 2018), we are planning to move all of our online services to Transport Layer Security (TLS) 1.2+ to provide best-in-class encryption, and to ensure our service is more secure by default.

 

As part of this plan, we’ll be retiring 3DES beginning February 28, 2019.

 

In order to help you prepare for this change, we will be providing reports for you to track your TLS 1.0/1.1 and 3DES usage. These reports will be available starting January 1, 2019.

 

[How does this affect me?]
As of February 28, 2019, we’ll begin retiring 3DES. As a result, connections to Microsoft using the cipher 3DES will not work.

 

[What do I need to do to prepare for this change?]
You need to ensure that all client-server and browser-server connections using 3DES to connect to Office 365 services have been updated.

 

 

Source from Office 365 message center: View this message in the Office 365 message center

More information: Preparing to use TLS 1.2 in Office 365