Downgrading php from 7.0 to 5.0

Php7 is installed by default on Ubuntu 16.04. 

The copy of gregarius, an RSS aggregator / reader uses php revision greater than 4.  Many of the mysql php core functions, and string editing is needlessly mangled in 7.0, and editing and updating the gregarius package is a very large task.

It is easier to downgrade the php for now than editing gregarius.  FWIW gregarius is pretty much dead in support after 2006, very old, which is sad since it is a nice stable tool.

it requires mysql, but luckily the downgraded php 5 works along with the mysql extensions.

Procedure snarfed from another blog to remove php 7 and install 5.6 from another repository, ondrej.

Remove all the stock php packages
List installed php packages with dpkg -l | grep php| awk '{print $2}' |tr "\n" " " then remove unneeded packages with sudo aptitude purge your_packages_here or if you want to directly remove them all use :

sudo apt-get purge `dpkg -l | grep php| awk '{print $2}' |tr "\n" " "`

Add the PPA

sudo add-apt-repository ppa:ondrej/php

If you get add-apt-repository: command not found run the following command first :

sudo apt-get install software-properties-common

Install your PHP Version

sudo apt-get update
sudo apt-get install php5.6

You can install php5.6 modules too for example

sudo apt-get install php5.6-mbstring php5.6-mcrypt php5.6-mysql php5.6-xml

Verify your version
If you have installed php5.6-cli

sudo php -v

If you don't have php5.6-cli, put this on a .php file

<?php 
      //outputs php configuration info
      phpinfo(); 
?>

restarting apache

dpkg-reconfigure phpmyadmin

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