sudo mkdir -p /opt/postal/application sudo wget sudo tar xvf most up-to-date.tgz -C /choose/postal/application sudo chown -R postal:postal /choose/postal sudo ln -s /opt/postal/app/bin/postal /usr/bin/postal Notice: Produce a file below /and many others/apt/sources.listing.d, not the /etcetera/apt/resources.list file where by the distribution's Formal repository addresses can be found... https://johnathanseqah.tribunablog.com/detailed-notes-on-whmcs-install-40868639