Невозможно установить PHP 7.1 на Debian Stretch

Я пытаюсь установить PHP 7.1 на Debian Stretch, и я получаю эту ошибку:

root@67a59862eeed:/var/www# apt install php7.1-apcu php7.1-bcmath php7.1-cli php7.1-curl php7.1-fpm php7.1-gd php7.1-intl php7.1-mcrypt php7.1-mysql php7.1-soap php7.1-xml php7.1-zip
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'php-apcu' instead of 'php7.1-apcu'
php7.1-gd is already the newest version (7.1.16-1+ubuntu18.04.1+deb.sury.org+1).
php7.1-mysql is already the newest version (7.1.16-1+ubuntu18.04.1+deb.sury.org+1).
php7.1-xml is already the newest version (7.1.16-1+ubuntu18.04.1+deb.sury.org+1).
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-cli : Depends: php7.1-opcache but it is not going to be installed
Depends: libc6 (>= 2.27) but 2.24-11+deb9u3 is to be installed
php7.1-curl : Depends: libcurl4 (>= 7.44.0) but it is not installable
php7.1-fpm : Depends: php7.1-opcache but it is not going to be installed
Depends: libc6 (>= 2.27) but 2.24-11+deb9u3 is to be installed
php7.1-intl : Depends: libicu60 (>= 60.1-1~) but it is not installable
php7.1-zip : Depends: libc6 (>= 2.27) but 2.24-11+deb9u3 is to be installed

Вот что я делаю:

$ apt install apt-transport-https ca-certificates
$ wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
$ sh -c 'echo "deb https://packages.sury.org/php/ stretch main" > /etc/apt/sources.list.d/php.list'
$ apt update

Похоже, моя текущая версия libc6 является последней версией (2.24-11). Я не знаю, как решить это.

Не могли бы вы мне помочь, пожалуйста ?