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



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.




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.




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














*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 located here.
    • Lync Room System (a.k.a. SRSv1)
      • LRS Options - Upgrading SRSv1 (LRS) Systems to SRS v2 – Further guidance is coming soon


The following devices currently do not support TLS 1.2, but are actively being reviewed and we should provide further guidance later.  Keep checking back here for updates.


  • Skype Room System (a.k.a. 'SRSv2' or Rigel)
  • Surface Hub


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


Skype for Business Server or Lync Server on-premises

Skype for Business Online


This article

Skype for Business Server or Lync Server on-premises

Federation with other customers or partners in Office 365 (current or future)


This article

Skype for Business Server or Lync Server on-premises

Exchange Server


This article

Exchange Server on-premises

Skype for Business Online



Follow the guidance in the Exchange blog series.

Cloud Connector Edition (CCE)

Skype for Business Online


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)



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.



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. 



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 3rd 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.   




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.



Regular Contributor

I have asked in the forums in March i think (when it was still planned to switch earlier) if we really need to do something about Windows 7. Didn't get 100% answer. But here it says that Windows 7 has no default support for TLS 1.2 (i know that, but IE11 works perfectly on Win7 and it supports TLS 1.2, so maybe if an app/browser has support it can work without changing anything on the OS). So, we MUST do something about this with Windows 7?

@Oleg K, as per https://support.microsoft.com/en-us/help/4057306/preparing-for-tls-1-2-in-office-365 :


  • If you have Windows 7 clients connected to Office 365, make sure that TLS 1.2 is the default secure protocols in WinHTTP in Windows. For more information see KB 3140245.

So yes, there's something to be done in Windows 7, explained here https://support.microsoft.com/en-us/help/3140245/update-to-enable-tls-1-1-and-tls-1-2-as-a-default-s...


I believe Internet explorer 11 manually establishes the highest version of TLS as default (that's just my belief, have not contrast that yet), and as stated in the article "This update will not change the behavior of applications that are manually setting the secure protocols instead of pass the default flag." Referring with the default flag to WINHTTP_OPTION_SECURE_PROTOCOLS, for the  DefaultSecureProtocols registry entry.

Senior Member

Can I ask for clarification that Lync 2010 Hybrid customers are "required" to upgrade to SfB Server 2015 prior to October 31 2018? 

Occasional Contributor

@Pamela Arimoto Am I understanding correctly that Lync 2010 customers will not have a direct migration path to SfB online after October 31st?


Hi @Rob Kennedy and @Clayton Jay Martin - Lync Server 2010 is not in scope for TLS 1.0/1.1 disable support.  Refer to: https://blogs.technet.microsoft.com/nexthop/2018/04/18/disabling-tls-1-01-1-in-skype-for-business-se...


If you are still running an On-Premises Lync Server 2010 Hybrid with Skype for Business Online environment you will need to take steps to ensure connectivity beyond the deprecation date.  That could include upgrading to a version of On-Premises server that does support TLS 1.0/1.1 disabling, or it could mean accelerating migration to 100% Online for your Lync/Skype for Business workloads.  

Senior Member

Thanks Corbin. The Nexthop article you reference discussed disabling TLS 1.0/1.1 rather than enabling TLS 1.2. Isn't the requirement for October 31 2018 to enable TLS 1.2? This article published yesterday appears to be the first announcement stating that Lync 2010 won't support TLS 1.2 and isn't supported for hybrid which doesn't leave a great deal of time to make alternate plans.

Occasional Contributor

@Rob Kennedy - The Oct 31 date was never about enabling TLS 1.2, as TLS 1.2 is already enabled within Office365 and secured communications can succeed over that protocol version today if the client endpoint supports TLS 1.2 (otherwise it would succeed over TLS 1.1 or TLS 1.0).  The Oct 31 date has always been about enforcing and requiring a minimum of TLS 1.2 for secured communications with Office365, which requires that TLS 1.0 and TLS 1.1 be disabled and restricted from TLS cipher negotiations.




The NextHop blog article from April 2018 explicitly states that Lync Server 2010 is out of scope and will not function in a TLS 1.2 enforced configuration, so the information has been publicly available since April 2018.  If you've got hybrid established to Office365 via Lync Server 2010, then you absolutely need to get your topology updated to at a minimum Lync Server 2013 (ideally Skype for Business Server 2015) in order to keep hybrid functional once MSFT makes the changes on Oct 31.

Senior Member
I would disagree that the article is clear on support for hybrid . The theme of the nexthop article is very much focused on disabling TLS 1.0/1.1 for the purposes of security and PCI compliance. I'm aware that O365 is already enabled for TLS 1.2, the issues is getting on prem infrastructure ready for TLS 1.2. The below KB article clearly states that TLS 1.2 has to be enabled and TLS 1.0/1.1 can remain enabled. I agree that the next shop states that Lync 2010 is out-of-scope of disabling but what it doesn't state is that Lync Server 2010 won't be supported for TLS 1.2 or Hybrid.
"Using TLS 1.2 with Office 365 does not mean you must have TLS 1.0/1.1 disabled in your environments by October 31, 2018. If parts of your environment require the use of TLS 1.0 and 1.1 on or after October 31, 2018, you can leave the older protocol versions enabled. However, TLS 1.2 will have to be enabled and used for communication with Office 365 to avoid any interruption in service."
Occasional Contributor

I'll concede the point that the blog post (this one) is primarily about the PCI DSS 3.2 standards.  However, I tend to view the PCI DSS 3.2 and the O365 enforcement as one in the same, because many customers are viewing it that way.


For 2010 hybrid, you've really got a few access methods for Hybrid:

Edge Servers to O365 (hybrid and federation)

PowerShell on FE's (for user moves to O365)

Client Access to O365 (S4BO)

Client Access to O365 (ExO)

Client Access to O365 (AzureAD)

Client/Server access to AD-FS


Assuming you've got a Windows Server OS with TLS 1.2 enabled today, you could examine Wireshark/NetMon/MessageAnalyzer for #1 and #2 above for your flows to O365 and determine what TLS protocol is being negotiated.  If TLS 1.2 is used, then in theory, you don't have to do anything with on-premises server infrastructure and things will probably remain functional after 31-Oct.  If TLS 1.2 is not used (even though the host OS has it enabled), then you have your answer.  I actually don't have a 2010 lab to test this with, so I can't tell you authoritatively unfortunately.


Either way, with 2010 out of mainstream support (and the fact that many voice pieces in the hybrid topology now require a 2015 edge server and FE in order to function with all call flows), it likely is not the best approach to leave 2010 in place and a take a gamble.


Sorry, let me clarify; @Trevor Miller has it correct.  As I have used it in this discussion, the terminology "TLS 1.0/1.1 disable support" = "enable TLS 1.2".  TLS 1.2 requires updates to Skype for Business Server 2015 and Lync Server 2013* (and extensive dependency updates to .Net, SQL, and the OS in some cases).  Lync Server 2010 was never in scope for software updates to enable it to use TLS 1.2.  We appreciate the feedback and will work to more clearly, explicitly call out the Hybrid scenarios here and in the On-Premises blog series.  


*Lync Server 2013 is a special case - be sure to read the On-Premises blog series carefully to understand our stance.  While Lync Server 2013 can be updated to use TLS 1.2 - you cannot disable TLS 1.0/1.1 on a Lync Server 2013 Front End or Standard Edition machine; we did this for back compat, Federation and Hybrid scenarios.  

Regular Visitor
Hi there, The link for more guidance on Lync Room Systems appears to have restricted access. Would you be able to share information on how to get these systems up to date? I'm specifically concerned about the Crestron RL2, since I have a few of these in my environment. I would be thrilled to get them on SRS v2! Kind regards, Charlie
Regular Visitor

@Pamela Arimoto I also would like to see the article regarding room systems. I have a Crestron RL1, which has been upgraded to 15.15.12. I'm not sure if that is enough.


@Pamela Arimoto, when you say CU10 for Lync 2013, do you mean the 10th CU in the list.

  • December 31, 2014 cumulative update (5.0.8308.866)

Or do you mean the lastest CU that came out in July of 2018? Sorry if this sounds like a dumb question, I just don't see a reference to CU 10 anywhere.


@Jacob Jones we're specifically referring to the July, 2018 Update for Lync Server 2013 not an individual component fix from that list.  2013 CU10 = July 2018; we will clarify in the blog, thanks for raising that!

Frequent Visitor

For the "Lync Room System (a.k.a. SRSv1)" you say "LRS Options - Upgrading SRSv1 (LRS) Systems to SRS v2 – Further guidance is coming soon". All I can say to that is I hope the guidance will state that support for TLS 1.2 is being included in an upgrade or update coming soon for current SRSv1 Systems. Some SRS v1 customers who are all in with Microsoft have already upgraded to TLS 1.2 elsewhere and are anxiously waiting on the update to SRS v2. 



how we can identify how many clients affected in our environment. we are using skype for business online



how we can identify how many clients affected in our environment. we are using skype for business online and what will the impact to the users if we failure to upgrade the client to office2016 or skype 2016


How about Skype for business update CU 6 to support TLS 1.2 but don't disable TLS 1.0 for Lync phone edition ? 

Senior Member

We don't want to disable TLS 1.0 / 1.1. If we just want to enable TLS 1.2 on SFB/Lync onprem do we have to do all the stuff mentioned here. 

- 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.


Can someone explain just the enable TLS 1.2 Scenario. 


Best Regards - Bueschu



Is there any news on Skype Room Systems and the surface hubs?  


Kind Regards, 


Senior Member

Am I missing something? The requirements for Skype:

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

in essence say that any Skype for Business 2016 clients older than the April 2018 version will not work and/or are not supported after the October 31, 2018 mandate of TLS 1.2.  That is only 6 months of support.  Microsoft states in multiple articles that we are supported for 18 months using the Semi-Annual channel. Here:




We cannot get all our clients upgraded by that time and the above article was posted only 1 month ago.  This is not enough lead time.  Can you please explain the version requirements and limited 6 months of support?


Best regards,



Skype is part of office 365 upgrade. whether we need to upgrade the office version . if we need to upgrade which version of office will support Tls1.2


for windows 7, they have requested to install KB to support TLS1.2 for the office365 communication. whether we need to upgrade officeproplus+windows 7 or windows 7 alone works

Hello Microsoft, 

I would like to echo a couple other requests for information. 


Is there any news on Skype Room Systems and the Surface hubs?

We have a number of these deployed globally with hundreds of uses per week.    


Allowing testing time, change-management and notifications, any changes in this area area already into the danger-zone for IT departments to handle this efficiently and effectively.    We need to hear back on updates ASAP. 


In other words - It is time to change '...we should provide further guidance later.  Keep checking back here for updates.'.  into real updates and software delivery.   



Regular Visitor

I have to agree with @William Adams.  It's been a month and a half since this blog post, and we haven't heard what to do about the Skype Room Systems.  This is putting a pretty substantial strain on us--we've stalled a few deployments of new rooms with Crestron's RL2, and are reworking alternatives since we don't have information.  @Pamela Arimoto are you able to offer any updates?


Kind regards,


Occasional Visitor

I was informed by Microsoft while I was in their Seattle office that the date for LPE phones (only) has been moved to December 31st, 2018


Please confirm. 

It may be prudent that this article be updated with the new date as well, this Oct 31st date is causing slight panic.