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Which Type of communication is used dependents by the DLL Version which is used from the Application. This means you need already to decide by the installation which communication type you want to use.
Troubleshoot
Allow Citrix Custom Custom Virtual Channel
If you have problems with finding the signature device the reason can be a police which blocks custom virtual channels. In case of problems, check out the Event Viewer for possible blocking events.
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To fix the issue, you need to configuring the Citrix virtual channel allow list policy. You can either do this in the Studio:
or inside the registry
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Policies\Citrix\VCPolicies
REG_MULTI_SZ
VirtualChannelWhiteList = "=disabled="
related links:
Virtual channel allow list now enabled by default | Citrix Blogs
Disable USB forwarding of Signaturpad
If you want to use the StepOver Citrix Extension, you need to disable the forwarding of the signature device by Citrix it self, because this will disable the access to the signature device to our Client component.