php7.1-Zip Installation unter Ubuntu 18.04

wie der Titel bereits erklärt, muss ich das Zip-Modul aus PHP 7.1 unter Ubuntu 18.04 installieren. Bei jedem benutze ich den Befehl 

Sudo apt-get install php7.1-Zip

und die folgende Ausgabe.

Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 php7.1-Zip : Depends: libzip4 (>= 1.0) but it is not installable
E: Unable to correct problems, you have held broken packages.

Der Versuch, libzip4 zu installieren, funktioniert ebenfalls nicht. 

Reading package lists... Done
Building dependency tree
Reading state information... Done
Package libzip4 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'libzip4' has no installation candidate

Kann jemand bitte versuchen zu helfen. Google hilft leider auch nicht weiter.

Elias