Hello, I have move my CentOS servers to Debian 9 server over ISPConfig 3.1.11 After install, I continued with .. https://www.howtoforge.com/tutorial/how-to-install-php-5.6-and-7.1-on-debian-9-stretch/ And in Php 5.6 version, ./configure --prefix=/opt/php-5.6 --with-pdo-pgsql --with-zlib-dir --with-freetype-dir --enable-mbstring --with-libxml-dir=/usr --enable-soap --enable-calendar --with-curl --with-mcrypt --with-zlib --with-pgsql --disable-rpath --enable-inline-optimization --with-bz2 --with-zlib --enable-sockets --enable-sysvsem --enable-sysvshm --enable-pcntl --enable-mbregex --enable-exif --enable-bcmath --with-mhash --enable-zip --with-pcre-regex --with-pdo-mysql --with-mysqli --with-mysql-sock=/var/run/mysqld/mysqld.sock --with-jpeg-dir=/usr --with-png-dir=/usr --enable-gd-native-ttf --with-openssl=/opt/openssl --with-fpm-user=www-data --with-fpm-group=www-data --with-libdir=/lib/x86_64-linux-gnu --enable-ftp --with-kerberos --with-gettext --with-xmlrpc --with-xsl --enable-opcache --enable-fpm configure command, says ERROR and STOP. checking for pkg-config... /usr/bin/pkg-configconfigure: error: Cannot find OpenSSL's libraries root@mail:/usr/local/src/php5.6-build/php-5.6.33# I need Php 5.6 too, what's wrong, ? I followed the tutorial step by step and Php 7.1 and Php 7.2 are working fine. Thanks Nestor Mazza
