Enforcement of TLS 1.2 for connections to Microsoft Defender ATP

To maintain the highest security standards and provide the best-in-class encryption to our customers, Microsoft Defender ATP is deprecating the use of TLS 1.0 and 1.1. Customers and partners will be required to use TLS 1.2 and above for all communications with their API integrations.

Why: 
The use of TLS 1.2 is a recommended security best practice that provides a higher degree of privacy and data integrity over previous versions and is required to maintain compliance with the latest industry standards. 

When: 
On March 16, 2020, all connections to your Microsoft Defender ATP instance will require that calling code and programs use TLS 1.2. Code and packages that connect to Microsoft Defender ATP APIs using lower TLS versions will no longer succeed. 

Required Action: 

Verify that your API integrations are compliant with TLS 1.2 by March 1, 2020.  If you're not already using TLS 1.2 or higher, update your code version to make it compatible with TLS 1.2. 

As always, let us know if you have concerns or questions. We're here for you. 
Open a case ticket with our technical support team with a subject of ‘Deprecation of TLS 1.1 and 1.0’ if you require assistance or further details regarding this matter. 

Additional resources: 

If you currently use TLS 1.0, evaluate your TLS 1.2 readiness and develop a migration plan with the testing described in Solving the TLS 1.0 Problem.