Preparing for TLS 1.0/1.1 Deprecation - O365 Skype for Business

[Pamela Arimoto]

INTRODUCTION

The purpose of this blog post is to provide the necessary guidance for our Skype for Business Server, Lync Server, and Skype for Business Online customers to prepare for the deprecation of TLS 1.0 and 1.1 in Office 365. 

Please carefully review all the information in this blog post as you prepare for the mandatory use of TLS 1.2 in Office 365.  Note that there may be many dependencies and connectivity considerations in your environment so extensive planning and testing is advised.

BACKGROUND

We are planning to discontinue support for Transport Layer Security (TLS) versions 1.0 and 1.1 in Microsoft Office 365 on October 31, 2018.  This was previously announced in the following support article. https://support.microsoft.com/en-us/help/4057306/preparing-for-tls-1-2-in-office-365

This change will provide our customers with the best-in-class encryption for our customers.  For more details on TLS, please consult the following whitepaper: here

For additional background understanding of TLS (and a great resource for Exchange customers), see the following blog post.

HOW TO PREPARE

If you would like to prepare your environments for the upcoming TLS 1.2 change, there are three general scenarios you should review and, if applicable to your organization, adequately plan and prepare for.

1. Lync/Skype client connectivity to Office 365
2. On-premises server integration w/Office 365
3. 3rd party integration with Skype for Business Online

We will cover each of these scenarios independently in the following sections.

Lync/Skype client connectivity to Office 365

Lync and Skype for Business clients may connect to Skype for Business Online, Exchange Online or both depending on where the account for these services are homed (online or on-premises). For example, if a Skype for Business client has their account homed in Lync Server 2013 on-premises, the client will still connect to Exchange Online if respective mailbox for the user is homed in Office 365.

As such, you need to follow the proceeding guidance if you fall into one of the following 3 client connectivity scenarios that has been flagged as ‘Preparation required”.

Mailbox Location	Lync/Skype account location	Preparation Required
Online	Online	Yes
On-premises	Online	Yes
Online	On-premises	Yes
On-premises	On-premises	No*

*although you are not required to prepare for client connectivity scenarios, you still may be required to remediate your on-premises infrastructure if you federate with any customers that reside in Skype for Business Online.  This scenario will be covered further in the next section.

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

• Lync 2013 (Skype for Business) Desktop Client, MSI and C2R, including Basic 0.5023.1000 and higher
• Skype for Business 2016 Desktop Client, MSI 0.4678.1000 and higher, including Basic
• Skype for Business 2016 Click to Run Require 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 on Mac 16.15 and higher
• Skype for Business for iOS and Android 6.19 and higher

The following clients and devices do not fully support TLS 1.2, and therefore, you must transition to a fully TLS 1.2 capable version in the list.

• Lync for Mac 2011
• Lync 2013 for Mobile - iOS, iPad, Android or Windows Phone
• Lync "MX" Windows Store client
• All Lync 2010 clients
• Lync Phone Edition.  There is further guidance provided for these devices is located here.
•  Lync Room System (a.k.a. SRS v1) –  LRS has reached end of support on October 9, 2018 and will not be updated to support TLS 1.2. Customers should consider migrating to SRS V2. See details here.

The following devices are actively working on supporting TLS 1.2 and are committed to providing support for TLS 1.2 before TLS 1.0/1.1 deprecation.

Skype Room System (a.k.a. 'SRSv2' or Rigel)  and Surface Hub guidance - 

Microsoft Teams Rooms (previously Skype Room System V2 SRS V2) support TLS 1.2 since December 2018.  Room device should have Microsoft Teams Room app version 4.0.64.0. ( See Release Notes). The changes are backward and forward compatible.  Surface Hub released TLS 1.2 support in May 2019.

TLS 1.2 support for Microsoft Teams Rooms and Surface Hub products also requires server side code changes:

• Skype for Business Online server changes were made live in April 2019 and now support connecting Microsoft Teams Rooms & Surface Hub devices using TLS 1.2.
• Skype for Business Server customers need a cumulative update install for them to use TLS 1.2 with Teams Rooms Systems and Surface Hub.
• Skype for Business Server 2015 – This is CU9 that is already released in May 2019.
• Skype for Business Server 2019- This is CU1 that was previously planned for April 2019 but is delayed to June 2019.

Skype for Business on-premise customer should not disable TLS 1.0/1.1 prior to installing specific CUs for SfB Server.

In addition to the preceding client remediation, it is important to ensure that the underlying OS and default browser supports TLS 1.2. For Microsoft OS support, you can consult our TLS whitepaper.  Note: Windows 7 by default does not have TLS 1.2 enabled by default.  The aforementioned whitepaper includes guidance on how to enable TLS 1.2 in Windows 7.  The following link will provide you with guidance on TLS 1.2 capability for browsers. https://en.wikipedia.org/wiki/Transport_Layer_Security#Web_browsers

On-premises server integration w/Office 365

There are several hybrid topologies that are covered under this scenario.  This includes any integration or Hybrid with Skype for Business Online or Exchange Online.  For your reference, all the supported on-premises Skype to Exchange integration scenarios are covered here.

The following table provides an overview of the scenarios that require preparation and where to find the respective guidance.

Deployed on-premises	Integration/Hybrid with	Preparation Required	Guidance
Skype for Business Server or Lync Server on-premises	Skype for Business Online	Yes	This article
Skype for Business Server or Lync Server on-premises	Federation with other customers or partners in Office 365 (current or future)	Yes	This article
Skype for Business Server or Lync Server on-premises	Exchange Server	Yes	This article
Exchange Server on-premises	Skype for Business Online	Yes	Follow the guidance in the Exchange blog series.
Cloud Connector Edition (CCE)	Skype for Business Online	No	CCE already communicates with Skype for Business Online with TLS 1.2 only.
Skype for Business Server or Lync Server on-premises	Exchange Server on-premises	No.   (ensure you do not federate with customers in Office 365 as described in the first scenario)	N/A

If your organization falls under the first four scenarios, you are required to upgrade your on-premises server environment to one of the following versions.

• Skype for Business Server 2015 CU6 HF2 6.0.9319.516 (March 2018 update) and higher on Windows Server 2012 (with KB 3140245 or superseding update), 2012 R2 or 2016
• In-place Upgraded Skype for Business Server 2015, with CU6 HF2 and higher on Windows Server 2008 R2, 2012 (with KB 3140245 or superseding update), or 2012 R2
• Lync Server 2013 CU10 or higher.  https://support.microsoft.com/en-us/help/2809243/updates-for-lync-server-2013. Any supported OS for Lync Server 2013 – 2008 R2 – 2012 R2; https://technet.microsoft.com/en-us/library/gg398588(v=ocs.15).aspx

If you are a customer that is running Lync Server 2010, we recommend that you upgrade to Skype for Business Server 2015 HF2 6.0.9319.516 or higher.  Note: Hybrid or integration scenarios with Office Communications Server 2007 R2 or earlier are not supported. 

• For post CU6 HF2 steps required for SFB Server 2015 – please refer to https://blogs.technet.microsoft.com/nexthop/2018/04/18/disabling-tls-1-01-1-in-skype-for-business-se...
  Post CU10 steps required for Lync Server 2013 are exactly the same as SFB Server 2015.

If you want to confirm Skype for Business Server TLS 1.2 support has been properly configured please install On-Premises Diagnostics for Skype for Business Server and execute 'Check to see if TLS 1.0/1.1 deprecation is properly configured' diagnostic. For more details please refer to How to use OPD.

3rd Party integration with Skype for Business Online

Skype for Business Online provides several supported SDKs and APIs.  If you are using a product from a 3^rd party vendor that integrates with the SDKs or APIs, then consult your vendor to ensure that it fully supports TLS 1.2.  If you have written a custom in-house application that integrates with Skype for Business Online via these APIs and SDKs, then it is highly recommended that you follow the guidance in our TLS white paper.  The white paper provides guidance to ensure your application is fully TLS 1.2 capable and provide guidance on how to validate through testing.   

OTHER CONSIDERATIONS

Your organization’s environment may be comprised of various networking or security devices that may include; proxy servers and load balancers, or other networking components.  Be sure to validate TLS 1.2 supportability, test carefully, and contact the vendor if needed.