Starting with the July 2017 update for Dynamics 365 (online) we will begin requiring connections to customer engagement applications to utilize TLS 1.2 (or better) security. This aligns with updated Microsoft and industry security policies and best practices, and you may be required to take actions to maintain connectivity to Dynamics 365 Customer Engagement applications. Please review the following information to help you identify if you are impacted and what steps you may need to take.
TLS stands for “Transport Layer Security,” and is a protocol that is an industry standard designed to protect the privacy of information communicated over the Internet. TLS is used in many web browsers and applications that communicate over HTTPS and TCP.
Today, all Dynamics 365 Customer Engagement online versions support TLS 1.0, 1.1 and 1.2, but starting with the release of the July 2017 update for Dynamics 365 (online), which is version 9.0 of the Customer Engagement platform, we will begin blocking connections to the updated product from clients or browsers that are using TLS 1.0 and 1.1. Versions 8.x and 7.x of Dynamics 365 Customer Engagement will not be affected with this change, and will continue to provide support for TLS 1.0, 1.1, and 1.2 as they do today. Please note: This change only affects Microsoft Dynamics 365 (online), not on-premises versions.
All supported browsers for Dynamics 365 Customer Engagement (versions 7.x – Version 9.x) currently comply with the TLS 1.2 standards and will continue to work as before. However, if you have disabled the TLS 1.2 protocol on your browser or utilize a custom Windows client built with .NET 4.5.2 you will be affected and lose connectivity to organizations with the July 2017 update for Dynamics 365 (online), version 9.0.
If you have deployed a non-Windows application that connects to a Dynamics 365 Customer Engagement instance you will need to verify that the technology stack you used supports TLS 1.2
Additional Information: Blog Post: Microsoft Secure Blog > TLS 1.2 support at Microsoft