How to Install an older version of php using apt-get?

Question

I have this older package in this exact version that I want to install on Ubuntu.

https://launchpad.net/ubuntu/+source/php5/5.3.10-1ubuntu3.20

Answer 1

to find out what different versions of a package is available in the enabled repository

apt-cache policy 

in your case

apt-cache policy php5

select the version that you want to install and then type

sudo apt-get install pkgname=version

in your case

sudo apt-get install php5=5.3.10-1ubuntu3.20

before running any of the above commands, it is better to update the apt-cache first. To do it, run

sudo apt-get update