Konnte nicht finden, dass jedes Paket von regex 'php5.6'

Ich versuche, ein upgrade von PHP 5.5.38 zu PHP 5.6. Ich bin nach Anleitung verfügbar auf SO, aber ich bin immer folgende Fehlermeldungen:

sudo apt-get -y install php5.6 php5.6-mcrypt php5.6-mbstring php5.6-curl php5.6-cli php5.6-mysql php5.6-gd php5.6-intl php5.6-xsl
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package php5.6
E: Couldn't find any package by regex 'php5.6'
E: Unable to locate package php5.6-mcrypt
E: Couldn't find any package by regex 'php5.6-mcrypt'
E: Unable to locate package php5.6-mbstring
E: Couldn't find any package by regex 'php5.6-mbstring'
E: Unable to locate package php5.6-curl
E: Couldn't find any package by regex 'php5.6-curl'
E: Unable to locate package php5.6-cli
E: Couldn't find any package by regex 'php5.6-cli'
E: Unable to locate package php5.6-mysql
E: Couldn't find any package by regex 'php5.6-mysql'
E: Unable to locate package php5.6-gd
E: Couldn't find any package by regex 'php5.6-gd'
E: Unable to locate package php5.6-intl
E: Couldn't find any package by regex 'php5.6-intl'
E: Unable to locate package php5.6-xsl
E: Couldn't find any package by regex 'php5.6-xsl'

Weiß jemand, was das Problem verursacht?

P. S.: ich bin auf Debian GNU/Linux 7 (wheezy)

InformationsquelleAutor Jérôme Verstrynge | 2016-10-03