I decided to use the tester’s repository on both the Gateway and the Workstation. So no difference while updating or upgrading them in the futur.
May I ask you one more thing @Patrick ?
On my Workstation I still have a lot of packages that the system would like to remove :
The following packages were automatically installed and are no longer required:
anon-shared-applications-kde anon-shared-default-applications anon-shared-desktop anon-shared-desktop-kde anon-shared-packages-dependencies
anon-shared-packages-recommended anon-torchat anon-workstation-packages-dependencies ca-certificates-mono cli-common libexif12 libgdiplus
libjsoncpp1 libmono-accessibility4.0-cil libmono-corlib4.5-cil libmono-data-tds4.0-cil libmono-i18n-west4.0-cil libmono-i18n4.0-cil
libmono-posix4.0-cil libmono-security4.0-cil libmono-system-configuration4.0-cil libmono-system-core4.0-cil libmono-system-data4.0-cil
libmono-system-drawing4.0-cil libmono-system-enterpriseservices4.0-cil libmono-system-numerics4.0-cil
libmono-system-runtime-serialization-formatters-soap4.0-cil libmono-system-security4.0-cil libmono-system-transactions4.0-cil
libmono-system-windows-forms4.0-cil libmono-system-xml4.0-cil libmono-system4.0-cil libmono-webbrowser4.0-cil mono-4.0-gac mono-gac mono-runtime
mono-runtime-common mono-runtime-sgen non-qubes-vm-enhancements thunderbird whonix-shared-packages-dependencies whonix-shared-packages-recommended
whonix-workstation-packages-dependencies whonix-workstation-packages-recommended xsel xul-ext-torbirdy
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Same on the Gateway :
The following packages were automatically installed and are no longer required:
anon-gateway-default-applications anon-gateway-packages-dependencies
anon-gateway-packages-recommended anon-shared-applications-kde
anon-shared-default-applications anon-shared-packages-dependencies
anon-shared-packages-recommended libcdio13 libdirectfb-1.2-9 libgles1-mesa
libiso9660-8 libvcdinfo0 libvlccore8 linux-headers-4.9.0-6-amd64
linux-headers-4.9.0-6-common linux-image-4.9.0-6-amd64
whonix-gateway-packages-dependencies whonix-gateway-packages-recommended
whonix-shared-packages-dependencies whonix-shared-packages-recommended
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Is that normal ? Can I keep it like this ? Is there a risk to autoremove ? Are these packages useful ?
EDIT : Error message was also present on the Gateway and I had to type the required command line :
sudo apt-get install non-qubes-whonix-gateway-kde
to make it disappear as I did on the Workstation.
Thank you again and again
You deserve 
