With Microsoft officially announcing that they will be upgrading Office365 to utilize the Skype for Business back-end, administrators will need to begin to take actions to prepare themselves and their users for the impact of this update.

Note: Since Skype for Business (hereafter, S4B) hasn’t been released to GA yet, this information is still pre-release and subject to change!

A few important things you should begin planning for:

Skype for Business will be provided as an update package to existing Lync 2013 clients

S4B will still remain “lync.exe” from an executable perspective and maintain the same major version number as Lync 2013. This greatly helps admins because Windows QoS policies should not need to be re-tooled and application whitelists will not need to be updated. Microsoft has not yet set a release date on the client update but an official announcement is likely to come soon.

Can I use Lync 2013 with a S4B Server?

The simple answer to this is “Yes!”. Lync 2013 clients will absolutely work when your user account is homed to a S4B pool. Remember that any new features of a S4B pool will not be presented to your user account until you update your client software from the Lync 2013 UI.

How do I control the UI presented to users?

This is a multi-faceted answer but largely boils down to two major points:

  1. If your Lync 2013 client has the latest S4B client update and your user account is homed on a S4B pool, upon first sign-in your client will automatically switch to the new S4B UI.
  2. If your Lync 2013 client has the latest S4B client update and your user account is homed on a S4B pool, you can override the automatic UI behavior by setting the EnableSkypeUI parameter within the Client Policies.

The EnableSkypeUI parameter, when set to $FALSE, ensures that the Lync 2013 UI is always used by any clients connecting to a S4B pool. This parameter is the only method you can use to ensure that the new Skype UI is not presented to users and can be controlled in a targeted fashion to help organizations manage a staged rollout of the new UI. I’ve included a table below that describes the various different combinations of clients, servers, and resulting client UI:

How does this effect Lync Online users?

Microsoft exerts total control over all policies and pools within Lync Online and have begun notifying customers that pending S4B upgrades will be coming within the next 90 days. Some organizations may not be ready to begin rolling out the new S4B UI but because Microsoft controls the pool upgrade process within Office365, there are limited options in controlling the client UI. Lync Online customers cannot customize Client Policies and all current Lync Online policies have a value of NULL for the EnableSkypeUI parameter. With the EnableSkypeUI parameter being NULL, clients will invoke the new UI if they have obtained the latest client update. At the current time there is no other recourse for Lync Online customers to prevent the Skype UI from being displayed, other than restricting the rollout of the latest client updates. I do believe that Microsoft will begin publishing additional client policies to allow organizations to disable the Skype UI, but customers will need to keep examining available client policies within Lync Online to discover which policies will be available:

Get-CsClientPolicy | Select Identity,EnableSkypeUI

What else should I know?

Microsoft continues to update TechNet with information regarding the upcoming Office365 updates. I strongly urge customers to examine the TechNet website for additional information and as always, I’ll update this post (or create additional posts) to reflect new changes as they are announced!

4/1/2015 Update

Microsoft has officially announced that two Client Policies will be available for customers to control the rollout of the Skype UI within Office365:


I strongly urge customers to examine these policies as they may not contain the same settings, such as DisableSaveIM, as the Client Policy you may be using!

9/9/2015 Update

Microsoft now has the following client policies available for customers to control the rollout of the Skype UI within Office365:


10/15/2015 Update

With Office 2016 being released there are some considerable changes to this EnableSkypeUI behavior.  You can no longer switch back and forth between the legacy Lync UI and the Skype UI when the Office 2016 suite is used.  If you are running the Office 2013 suite and April 2015 CU, you can still switch back and forth, but Office 2016 users will notice that the Skype UI will never change.  It is now a hard-coded setting and is enforced regardless of server version.

The Skype4B client, as a part of Office 2016, does still retain the “lync.exe” executable name although the version number of the software has been bumped to 16.0.