We are planning to discontinue support for 3DES in O365 Skype for Business starting on July 10, 2019.  Please refer to the following O365 Encryption guidance for 3DES retirement preparation - https://docs.microsoft.com/en-us/office365/securitycompliance/technical-reference-details-about-encr...



The following Office 365 Skype for Business clients and devices rely on 3DES and therefore must be updated or replaced:

    • Lync for Mac 2011
    • All Lync 2010 clients
    • Lync Phone Edition

To prepare your organization for the client connectivity scenarios, you should ensure that your clients meet the following minimum versions:

  • Skype for Business Click-to-Run - Requires the April 2018 Updates:
    •  Monthly and Semi-Annual Targeted - 16.0.9126.2152 and higher
    •  Semi-Annual and Deferred Channel - 16.0.8431.2242 and higher
  • Skype for Business 2019 volume license
  • Skype for Business 2016 Desktop Client, MSI 0.4678.1000 and higher, including Basic
  • Lync 2013 (Skype for Business 2015) Desktop Client, MSI and C2R, including Basic 0.5023.1000 and higher
  • Skype for Business for Mac 16.15 and higher
  • Skype for Business for iOS and Android 6.19 and higher
  • Certified Skype for Business Online Phones -  Further guidance is located here.