title: Install php5.6 in Debian 9
body: <p>How to install <code>php5.6</code> in the <em>Debian 9</em></p>
  
  <blockquote>
    <p>The following packages have unmet dependencies: libapache2-mod-php5 :
    Depends: libdb5.1 but it is not installable Depends: libonig2 (>=
    5.2.0) but it is not installable Depends: libssl1.0.0 (>= 1.0.1) but it is not installable Depends: apache2-mpm-prefork but it is not
    installable or apache2-mpm-itk but it is not installable Depends:
    php5-cli but it is not going to be installed E: Unable to correct
    problems, you have held broken packages.</p>
  </blockquote>