DPI scaling is a critical consideration when using high-resolution monitors (over 1920x1080) with Citrix Virtual Apps and Desktops. Without the proper product versions and configuration, the Citrix session could be displayed at resolutions and scales that diverge from the local client configuration, resulting in blurry text and incorrect sizing of graphics.   

This article lists the different DPI scaling modes, support requirements, and configuration options available with Citrix Workspace App (CWA) for Windows.

CWA for Windows can be configured in one of three DPI modes:

DPI matching (recommended)

CWA for Windows will match display resolution and DPI scale settings of the local Windows client to the Citrix session. This is the recommended mode for all cases that meet the following system requirements:

• Citrix Virtual Apps and Desktops 1912 LTSR* or newer
• Multi-session OS VDAs running on Windows Server 2016 or newer
• Single-session OS VDAs running on Windows 10 or newer  
• CWA for Windows 1912 LTSR or newer

Important considerations:

• Default mode starting with CWA for Windows 2206.  
• 1912 LTSR VDAs require that DPI matching be enabled for Virtual Apps (aka seamless or published apps) sessions using the registry key below. Without this key, the VDA will ignore the DPI scale settings of the client for all virtual app sessions, which may result in very small text and graphics. 

Location: HKLM\SOFTWARE\Citrix\Graphics
Name: EnableDpiSupport
Type: DWORD
Value: 1

• DPI matching is not supported with XenApp/XenDesktop 7.15 LTSR. Citrix recommends customers use CWA for Windows LTSR with these VDAs. As an alternative, DPI matching can be disabled for CWA for Windows 2206 using a group policy. 

Client-side scaling (compatibility mode)

CWA for Windows will upscale the Citrix session to match the DPI scale set on the local Windows client. This mode is intended as a temporary solution to support backward compatibility scenarios, where CWA for Windows may be used to connect to legacy XenApp/XenDesktop 7.15 LTSR environments, where DPI matching is not possible but the use of high-resolution monitors and DPI scales above 100% are needed on the client.

Important considerations:

• Text and graphics may appear blurry as a result of the upscaling (or stretching) of the Citrix session.
• May decrease performance when connecting to sessions using legacy graphics mode.
• Local App Access, RTOP, and other plugins that use the window positioning API do not work with Scaling.
• Seamless apps will “jump” between monitors to maintain correct scaling, this is by design.

DPI unaware (legacy mode)

CWA for Windows will ignore DPI scale settings on the local Windows client. In this mode, it is up the Windows OS to manage scaling of the CWA and the Citrix session, in the same way it does for any other application that is not DPI-aware. This mode is not recommended for use with DPI scales over 100%.

Important considerations:

• Default mode with all versions of CWA for Windows up to 2205.
• This mode is not supported with mixed DPI settings, where multiple monitors are connected to the local Windows client and configured with different DPI scales. For example: One monitor with a 100% DPI scale and another monitor with a 150% DPI scale.

Configuration Options

Settings can be configured through CWA for Windows group policy settings, or through the ‘High DPI’ settings under ‘Advanced Preferences’ in CWA for Windows up to version 2205. These settings are also available to configure using the Citrix Global App Configuration Service.
 

GPO configuration

To configure DPI scaling using the CWA for Windows Group Policy Object administrative template (administrators only)

1. Under the Computer Configuration node, go to Administrative Templates > Citrix Components > Citrix Workspace > DPI
2. Select High DPI policy.
3. Change the settings as required.
   • “No, use the native resolution” = DPI matching (recommended)
   • “Yes” = Client-side scaling
   • “Let the operating system scale the resolution” = DPI unaware
4. Click Apply and OK.
5. From a command line, run the gpupdate /force command.

Citrix Workspace app for Windows Advanced Preferences configuration

To configure DPI scaling using the graphical user interface:

1. Right-click the CWA for Windows icon in the Windows notification area (systray).
2. Select ‘Advanced Preferences’ and click ‘High DPI’.
3. On the page that opens, change the settings as required. Starting from CWA 2206 and above, the default option is "No, use the native resolution". In earlier versions, the default option is "Let the operating system scale the resolution"
4. Click Save.
5. Changes will take effect for subsequent session connections.

Caution! Using Registry Editor incorrectly can cause serious problems that might require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

Starting with Citrix Receiver for Windows 4.10, improved support for handling higher DPI resolution in a session has been added.