Download the latest package from here

cd Downloads

sudo dpkg -i icaclient_version_number_amd64.deb

This will probably throw up in your face a million times due to dependency issues. If it does run the following to resolve them.

apt-get install -f

Once done let's get the certificates in place like this.

sudo ln -s /usr/share/ca-certificates/mozilla/* /opt/Citrix/ICAClient/keystore/cacerts/
sudo c_rehash /opt/Citrix/ICAClient/keystore/cacerts