Get the latest version directly from Citrix: https://www.citrix.com/downloads/workspace-app/linux/workspace-app-for-linux-latest.html.

Navigator to Debian Packages → Full Packages (Self-Service Support) → Citrix Workspace app for Linux (x86_64)/.

sudo dpkg -i icaclient_19.12.0.19_amd64.deb  
 
Selecting previously unselected package icaclient.
(Reading database ... 250480 files and directories currently installed.)
Preparing to unpack icaclient_19.12.0.19_amd64.deb ...
Unpacking icaclient (19.12.0.19) ...
Setting up icaclient (19.12.0.19) ...
Processing triggers for gnome-menus (3.36.0-1ubuntu1) ...
Processing triggers for desktop-file-utils (0.24-1ubuntu2) ...
Processing triggers for mime-support (3.64ubuntu1) ...

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