XenApp 6.x, XenApp 7.x, XenDesktop 7.x and Citrix Receiver 4.x include the interfaces required for compatibility with Microsoft’s old “v1” architecture VDI Plug-in for Skype™ for Business 2015 and Lync™ 2013.
Prior to the Citrix-Microsoft collaboration on a “v2” architecture for delivering the Skype for Business client from XenApp and XenDesktop which culminated in the HDX RealTime Optimization Pack 2.0 release in December 2015 and a corresponding update to the Skype for Business client, Microsoft promoted a “v1” solution consisting of a Citrix Receiver for Windows plug-in called the “VDI Plug-in”. Citrix and Microsoft continue to support the VDI Plug-in solution according to its lifecycle. The Microsoft VDI Plug-in packaged the Skype/Lync client as a headless plug-in to the Citrix Receiver. The VDI Plug-in was suitable for customers using the Skype for Business 2015 or Lync 2013 client exclusively with Windows devices (Windows 7, WES 7, Windows 8.x or Windows 10) and delivering the Skype or Lync client as part of a full virtual desktop. (See VDI plug-in prerequisites on Microsoft TechNet.)
Although the VDI Plug-in solution has been superseded by the HDX RealTime Optimization Pack and updates to the Skype for Business client, it will continue to be fully supported according to its lifecycle. This article describes how to install the Microsoft VDI Plug-in and provides a list of known issues. For feature limitations of the VDI Plug-in, refer to Known Limitations for VDI on the Microsoft TechNet site.

Overview

The Microsoft “v1” VDI Plug-in, designed as a plug-in to Citrix Receiver for Windows, optimized Skype/Lync audio and video in a Virtual Desktop Infrastructure (VDI) environment, prior to the introduction of the new “v2” architecture jointly developed by Citrix and Microsoft. The “v1” VDI Plug-in enabled Windows device users to make audio and video calls while preserving server scalability by offloading media processing to the user device.
Citrix continues to support the following deployments with the Microsoft VDI Plug-in:

• XenDesktop 7.x deployment of Windows 7 and Windows 8.1 Desktop OS machines

• XenDesktop 7.x deployment of Windows Server 2008 R2 machines with hosted Remote Desktop Service (RDS) desktops [not supported by Microsoft]

• XenApp 6.x deployment of Windows Server 2008 R2 published desktops [not supported by Microsoft]

• XenApp 7.x deployment of Windows Server 2008 R2 published desktops [not supported by Microsoft]

• VDI-in-a-Box 5.4 (XenDesktop 7.1 VDA) deployment of Windows 7 Desktop OS machines

Citrix has no plans to validate the VDI Plug-in solution with Windows 10 virtual desktops or with Windows Server 2012 published desktops.

The new HDX RealTime Optimization Pack v2 is now the only Microsoft-endorsed solution for delivering Skype for Business in a virtualized environment. (See announcement by Microsoft Corporate VP Brad Anderson.)

Note that Citrix can only support the software developed by Citrix. Citrix does not have access to the Microsoft VDI Plug-in source code. Therefore, customers encountering issues on configurations not supported by Microsoft, as highlighted above, may need to replicate their issue on a supported configuration if Microsoft technical support is required in order to resolve the issue, i.e. if the issue is outside the Citrix software.

If using the Microsoft VDI Plug-in, the Skype for Business 2015 or Lync 2013 client must be delivered as part of a full virtual desktop. Unlike the HDX RealTime Optimization Pack solution, the VDI Plug-in does not support delivery of the Skype/Lync client as a XenApp published/seamless application.

Smart card authentication is not supported with the VDI Plug-in.

The following combination of software was formally qualified by Microsoft as noted in Microsoft TechCenter Infrastructure qualified for Microsoft Lync:

• XenDesktop VDI Virtual Delivery Agent 7.1
  (Citrix recommends the 7.6.3 Long-Term Service Release or the latest 7.x Current Release)

• Citrix Receiver 4.1.02 for Windows
  (Citrix recommends the latest 4.x release)

• Virtual desktop OS: Windows 7 with Service Pack 1

• Endpoint OS: Windows 7 with Service Pack 1 or Windows Embedded Standard 7 with Service Pack 1

On XenApp 7.1/7.5 and XenDesktop 7.1/7.5, Citrix recommends applying hotfix ICAWS750WX64029 (not required with XenApp/XenDesktop 7.6 or above). For the list of issues resolved in this hotfix, refer to CTX140257 - Hotfix ICAWS750WX64029 - For VDA Core Services 7.1/7.5 for Windows Desktop OS (64-bit) - English.

For optimized delivery of the Skype/Lync client to Mac and Linux devices, see HDX RealTime Optimization Pack.

System Requirements

• Per Microsoft TechNet article jj205304, “The [VDI Plug-in] user must be homed on Lync Server 2013”. Skype for Business Server 2015 is not listed as a supported platform. Likewise, Office 365 / Skype for Business Online is not listed. Furthermore, Citrix has no plans to test the VDI Plug-in solution with Skype for Business Server 2015 or Office 365 / Skype for Business Online.

• Lync Server 2013 must be configured with EnableMediaRedirection set to True.

• 32-bit Microsoft VDI Plug-in installed on a Windows device running a supported version of Windows; for Microsoft VDI Plug-in installation requirements see Lync VDI Plug-in Prerequisites. Citrix Receiver for Windows requires the 32-bit version of the Microsoft VDI Plug-in on the device, even on a 64-bit Windows machine. The 64-bit version is not compatible with Citrix Receiver for Windows since the bitness of the VDI Plug-in must match the bitness of Receiver.

• A Skype for Business / Lync Server certificate installed on the user device as well as on the XenApp/XenDesktop server.

Note: If Microsoft Office is to be installed locally on the device, you must use the 32-bit version of Office

---

Instructions

To Install the Microsoft VDI Plug-in

1. Download the latest release of Citrix Receiver 4.x for Windows and install on the user device.

2. Download the Microsoft VDI Plug-in (32-bit) from the Microsoft Download Center.

3. Install the VDI Plug-in on the device. See Deploying the Lync VDI Plug-in.
   Note: Be sure to install the latest Microsoft updates.

4. Install the Skype/Lync Server certificate on the device.

To Validate the Configuration of Skype for Business / Lync

The recommended best practice is to use the Microsoft RDP client first to validate your Skype for Business / Lync configuration independent of any Citrix software, and then switch to Citrix Receiver. When you validate your configuration with the Microsoft RDP client, the bit version of the Microsoft Lync VDI Plug-in must match that of the RDP client and the Windows operating system, as described in Lync VDI Plug-in Prerequisites.

If you perform verification on a 64-bit Windows OS, substitute the 32-bit version of the Microsoft VDI Plug-in when you switch from RDP to ICA and the Citrix Receiver for Windows.

To validate proper pairing of the VDI Plug-in

When Skype/Lync and the VDI Plug-in have paired correctly, the icon under the Contacts list includes a green checkbox and the Audio Device settings appear as displayed in the following screen shot:

As noted on the above screen, audio device tuning is not supported when using the VDI Plug-in.

Troubleshooting Methodology

Issues Pairing the Skype/Lync client with the VDI Plug-in

When Skype/Lync and the VDI Plug-in are not paired correctly, then the icon under the Contacts list does not include the green checkbox and the Audio Device settings show the remote devices as displayed in the following screen shot:

In case of issues pairing the Microsoft Skype for Business / Lync client with the VDI Plug-in:

• Look for DHCP errors as these can cause connectivity between the Skype for Business / Lync client and the VDI Plug-in to become intermittent, with frequent disconnects.

• Restart the device.

• Make sure the endpoint OS is 32-bit and has the 32-bit VDI plug-in installed, not the 64-bit version.

• Make sure there is an exception on the Windows firewall for the Lync ports (or disable the firewall). Do this on both the endpoint and VDA. The list of ports used by Lync is here: http://technet.microsoft.com/en-us/library/gg398833.aspx. Ensure that any routers between the endpoints, VDAs and Lync server aren’t blocking the port; the endpoints and VDAs both need to be able to reach the Lync server.

• Ensure that the EnableMediaRedirection policy is set to True on the Lync server (see http://technet.microsoft.com/en-us/library/jj205154.aspx).  

• Make sure that the latest Skype/Lync updates from Microsoft have been installed.

  • The file version for c:\Program Files\Microsoft Office\Office15\LyncVdiPlugin.dll on the endpoint must be at least 15.0.4517.1504

  • The file version for c:\Program Files\Microsoft Office\Office15\Lync.exe on the VDA must be at least 15.0.4517.1504

• Ensure that an audio/video device is plugged into the endpoint.

• After establishing a connection to the VDA, use a tool such as Process Explorer to verify that LyncVdiPlugin.dll is loaded by the wfica32.exe process. Process Explorer can be found here: http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx. To check if the DLL is loaded, on the menu, go to Find, then Find Handle or DLL.

For more information about troubleshooting the Microsoft VDI Plug-in, see Troubleshooting the Lync VDI Plug-in.

Log Locations

To capture log files, complete the following:

1. In the main Skype/Lync window, go to Tools > Options > General.

2. For Logging, choose Full.

3. Select the checkbox for Also turn on Windows Event logging to collect troubleshooting information.

4. Collect the logs from the following locations:

• On the Lync Server: %localappdata%\Microsoft\Office\15.0\Lync\Tracing

• On the device: %localappdata%\Microsoft\Office\15.0\Lync\Tracing

To capture logs for the Virtual Delivery Agent (VDA), complete the following:

1. Use CTX130147 - Citrix Scout to run a CDF trace with XenApp/XenDesktop 7.x. The relevant trace modules for the VDA are:

• MF_DLL_CtxDvcApi

• MF_Driver_CtxDVC

• MF_Driver_Wdica

1. Upload the trace file to Citrix Insight Services (a.k.a. Tools-as-a-Service).

2. Review the trace on the Citrix Insight Services site.

Known Issues and Workarounds

Issue: When right-clicking on a voice message in and selecting Play, the message cannot be heard.

Workaround: Double-click on the voice message or click on the View More in Outlook link to open the voice message in Outlook; this enables the message to be heard through the speakers on the user device. 
Alternatively, if you select this icon  and choose Call Voice Mail, you can listen to the voice message through your USB headset.

Third-party Issues

Check directly with Microsoft for updates regarding the following issues:

• When a call starts, the audio volume on the device is reduced. Use the device audio controls to increase the volume.

• Camera is activated when user hovers mouse over the video preview if camera is present on the "server side" (host) computer (physically or virtually). Preview is shown, despite text on the screen that says video preview is not supported. Video fails to start for the rest of the call if the video preview was shown. The issue does not occur if a video call is started by right clicking a contact and selecting “Make video call” or by using the Meet Now dialog. This issue is caused by the fact that Skype/Lync, when paired with the VDI plug-in, still loads any webcam devices present on the [virtual] desktop. Therefore, the virtual webcam device provided by generic HDX Webcam Video Compression is loaded, locking the webcam and preventing Skype/Lync from using it. A possible workaround is to disable generic HDX Webcam Video Compression, which is turned on by default. This can be accomplished by configuring a policy on the Desktop Delivery Controller (DDC). The policy is under Multimedia Settings and is called “Multimedia Conferencing”. It is a machine-wide policy. The drawback to disabling generic HDX Webcam Video Compression is that users of other video conferencing applications, such as Citrix GoToMeeting, or users who do not have the VDI plug-in installed, will not be able to use their webcam in a XenApp/XenDesktop session.

For feature limitations of the VDI Plug-in, refer to Known Limitations for VDI on the Microsoft TechNet site. The VDI Plug-in is not supported on Windows Thin PC, Windows XPe, WES 2009 or Windows Server 2012 [R2]. The VDI Plug-in does not support smart card authentication and users must enter their credentials manually if their device is not domain-joined. And the VDI Plug-in solution does not support delivery of the Skype/Lync client as a seamless/published application.

This software application is provided to you as is with no representations, warranties or conditions of any kind. You may use and distribute it at your own risk. CITRIX DISCLAIMS ALL WARRANTIES WHATSOEVER, EXPRESS, IMPLIED, WRITTEN, ORAL OR STATUTORY, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NONINFRINGEMENT. Without limiting the generality of the foregoing, you acknowledge and agree that: (a) the software application may exhibit errors, design flaws or other problems, possibly resulting in loss of data or damage to property; (b) it may not be possible to make the software application fully functional; and (c) Citrix may, without notice or liability to you, cease to make available the current version and/or any future versions of the software application. In no event should the software application be used to support ultra-hazardous activities, including but not limited to life support or blasting activities. NEITHER CITRIX NOR ITS AFFILIATES OR AGENTS WILL BE LIABLE, UNDER BREACH OF CONTRACT OR ANY OTHER THEORY OF LIABILITY, FOR ANY DAMAGES WHATSOEVER ARISING FROM USE OF THE SOFTWARE APPLICATION, INCLUDING WITHOUT LIMITATION DIRECT, SPECIAL, INCIDENTAL, PUNITIVE, CONSEQUENTIAL OR OTHER DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. You agree to indemnify and defend Citrix against any and all claims arising from your use, modification or distribution of the software application.

This article contains information about XenDesktop 7, XenApp 6.x/7.x and Citrix Receiver 4.x Support for Microsoft Lync 2013 VDI Plug-in.

Deploying the Lync VDI Plug-in​