Update 01-02-2019: Citrix Receiver has not updated for a while and has been replaced by Citrix Workspace: https://www.citrix.com/downloads/workspace-app/linux/workspace-app-for-linux-latest.html but I still received error messages regarding "0.0.0.2 - Application No such file or directory. Verify your connection settings and try again." even after installing certificates and creating symbolic links for libidn. The internal storefront works without any issues, while the external one has some issues if using Mozilla Firefox or Google Chrome in Slackware64-current. This issue does not happen in Microsoft Windows 10.
After a bit of research and reading, I found this forum https://www.linuxquestions.org/questions/slackware-14/citrix-receiver-problems-due-to-missing-libidn-so-11-in-current-of-2018-06-21-a-4175632430/ where they listed this URL for Chrome: https://chrome.google.com/webstore/detail/citrix-workspace/haiffjcadagjlijoggckpgfnoeiflnem?hl=en as an "app" for Google Chrome. The "app" is working great so far. No need to install Citrix Receiver anymore, just point the "app" to the proper URL for your storefront and enjoy
Update 12-23-2018: In cases where there is a black square around the mouse pointer, follow the instructions in this page: https://support.citrix.com/article/CTX212013
Citrix Receiver is a virtualization client which allows to run applications and programs running on a Citrix server from within a browser connection
In the Microsoft Windows world, you can simply download and install an application that would start when you login to your computer and even allows to use single sign on (https://www.citrix.com/downloads/citrix-receiver/windows/receiver-for-windows-latest.html), but my laptop is Linux based and I prefer to use Citrix Receiver natively in Linux
In the past, you needed to run a multilib system to run Citrix Receiver (https://docs.slackware.com/howtos:network_services:citrix_client or https://alien.slackbook.org/blog/new-multilib-versions-of-glibc-and-gcc-for-slackware-current/), but luckily for all of us, now the 64-bit version of Citrix Receiver can be run on Firefox without an issue
1) Download Citrix Receiver from https://www.citrix.com/downloads/citrix-receiver/linux/receiver-for-linux-latest.html by choosing "Tarball Packages" and "Receiver for Linux (x86_64). Accept the license agreement and save the tar.gz file
2) Navigate to the location where you saved the the tar.gz file and extract it (tar vxf linuxx64-22.214.171.124.tar.gz in this case)
3) Run setupwfc as root and choose "1. Install Citrix Receiver for Linux 13.9.1"
4) Follow the prompts, making sure to select "n" for "Do you want to install USB support? [default n]:"
5) Follow steps "5. Add more SSL certificates" and "7. (64-bit only) Fix Firefox plugin installation" from https://help.ubuntu.com/community/CitrixICAClientHowTo
Note: If steps 5 and 7 from https://help.ubuntu.com/community/CitrixICAClientHowTo are not followed, error message "Cannot connect to "0.0.0.2 - Application No such file or directory. Verify your connection settings and try again." may display on the screen when trying to launch an application
6) Alternatively follow step "6. Configure Citrix Receiver" from https://help.ubuntu.com/community/CitrixICAClientHowTo if you want to map drives to allow access to files in the remote Citrix session
7) Create symbolic links, if needed, for libidn:
ln -s libidn.so.12.6.0 libidn.so.11
ln -s libidn.so.12.6.0 libidn.so
F. Bobbio C.