title: Couldn't find any package by regex 'php5.6'
body: <p>I am trying to upgrade from PHP 5.5.38 to PHP 5.6. I am following instructions <a href="https://stackoverflow.com/a/38737323/520957">available on SO</a>, but I am getting the following error messages:</p>
  
  <pre><code>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'
  </code></pre>
  
  <p>Does anyone know what is causing this issue?</p>
  
  <p><strong>P.S.</strong>: I am on Debian GNU/Linux 7 (wheezy)</p>