Product Documentation

System requirements

Jun 21, 2016


HDX RealTime Optimization Pack 1.8 supports the following Microsoft Lync configurations:

  • Microsoft Lync 2013 client
  • Microsoft Lync 2010 client
  • Microsoft Skype for Business server 2015
  • Microsoft Lync 2013 server *
  • Microsoft Lync 2010 server
  • Microsoft Lync Online (Office 365 hosted Lync Server 2013)
* We recommend you upgrade to HDX RealTime Optimization Pack 2.x if you are on Microsoft Lync 2013 server. 

HDX RealTime Optimization Pack 1.8 supports the following Citrix environments:

  • XenDesktop  5.6, 7, 7.5, 7.6 
  • XenApp 6.0, 6.5, 6.5 Feature Pack 1, and 6.5 Feature Pack 2 and Feature Pack 3 , XenApp 7.5, 7.6 

For more information about XenDesktop and XenApp editions that include Lync optimization, see
Skype for Business and Lync Delivery Feature Matrix.

HDX RealTime Optimization Pack 1.8 supports the following Citrix Receivers:

  • Receiver for Windows 4.x and 3.x
  • Receiver for Mac 12.x
  • Receiver for Linux 13.x and 12.x

HDX RealTime Optimization Pack 1.8 is not support on devices where Microsoft Office applications have been installed using ClickOnce. An error may occur when attempting to install HDX RealTime Optimization Pack 1.8 on these devices.

HDX RealTime Connector

You install HDX RealTime Connector on XenDesktop virtual desktops or on servers in your XenApp farm. Use this connector with the Skype for Business 2015 client in Lync UI mode and with the Lync 2013 client.

  • Supported operating systems:
    • Desktops: Microsoft Windows 7, 8, 8.1
    • Servers:
      • Microsoft Windows Server 2008 R2
      • Windows Server 2012 R2 – Note: Though Citrix successfully tested on this operating system, Microsoft does not list it as a supported operating system for Microsoft Lync.

  • Memory: minimum 4 GB RAM, 120 MB paging file
  • Disk space: minimum 100 MB available
  • Network interface: full-duplex Ethernet TCP/IP local network connection
  • Software:
    • DirectX 9 (minimum)
    • Microsoft .NET 4.0 SP1
    • Microsoft Lync 2013 SP 1 (32- or 64-bit)

Installation prerequisite

  1. Right-click the Microsoft Lync shortcut on your Desktop or in the list of programs in the Start Menu and choose Properties.
  2. In the Properties dialog box, click the Compatibility tab.
  3. On the Compatibility tab, ensure the Run this program as an administrator checkbox is cleared.

HDX RealTime Media Engine/Client Device

You install the HDX RealTime Media Engine on the client device.

See for client devices verified for HDX RealTime Optimization Pack.

Hardware requirements


  • Support for SSE3 instruction set
  • For CIF (standard) video, 1.4 GHz
  • For 720p HD (high definition) video, 2.8 GHz dual core


  • 50 MB disk space
  • 1 GB total RAM 

Supported operating systems

You can install HDX RealTime Media Engine on devices running any of the following operating systems:

  • Microsoft Windows 7, Microsoft Windows 8 and 8.1, Windows 2012 R2
  • Microsoft Windows devices: WES 7, WES 2009, Microsoft Windows XPe, or Microsoft Windows Thin PC (TPC)
  • Linux 32-bit (Ubuntu 14.04, Ubuntu 12.04, Ubuntu 10.04, or RedHat 6.2)
  • Linux 32-bit (SUSE Enterprise SP1/SP2)
  • Unicon claims support for the HDX Optimization pack for Microsoft Lync on eLux RP 4.3.0.
  • Mac OS X 10.10.x & 10.9.x

Requirements for audio and video calling:

  • RealTime Media Engine can support video calls in high-definition (HD) video. The RealTime Media Engine measures the speed of the user device and then encodes HD video if the camera, the host device, the bandwidth setting, and the remote endpoint support high-definition specifications.
  • Camera:
    • Most USB webcams are supported.
    • Minimum resolution: 320 x 240
    • Color space: 1420 or YUY2
    • Frame rate of at least 10 fps, 24 fps for HD video
    • Windows UVC driver
  • Audio input/output must be DirectSound-compatible and capable of 16-bit mono or stereo sound at 16,000, 32,000, or 44,100 samples per second. A USB headset is recommended.

Requirements for Lync-compatible audio devices:

HDX RealTime Connector supports Lync-compatible USB headsets, speaker phones, and phones. For full information about supported devices, see Skype for Business Solutions.

Third-party video drivers and Citrix HDX RealTime Optimization Pack for Microsoft Lync

The Microsoft Windows operating system installed on some thin client terminals often does not include Windows USB video class (UVC) drivers for web cameras, although these drivers have been included with standard Microsoft Windows XP and Vista operating systems since SP2. When you install a web camera on a terminal device, the installation program may report that it does not have required files.

We recommend that you use the standard Windows device drivers for webcams because vendor-supplied drivers can sometimes cause crashes and Blue Screen events on certain platforms (especially 64-bit Windows).