I want to know how to install PHP 5.3 on Ubuntu Server 18.04 LTS, because I have a system that requires PHP 5.3 only.
Is this possible?
Besides getting the usual warning regarding outdated packages, you should be able to compile PHP 5.3 on your system.
Taken from this post:
You will need these extra packages:
sudo apt-get install build-essential libxml2-dev checkinstall
In terminal - Download the package into tmp directory (or where ever you want it downloaded to)
cd /tmp && wget http://in1.php.net/distributions/php-5.3.29.tar.bz2
Untar and cd into directory
tar -xvf php-5.3.29.tar.bz2 cd php-5.3.29
Get everything ready and compile - if you get errors you may be missing some packages. You will have to google how to get these missing parts.
Create PHP 5.3 .deb file. This way you can easily uninstall later.
I just tried to compile this on my 18.04 machine and it worked fine. But you may need certain php modules for your project and you may have to find and compile those as well.
You may have to install some missing packages for the .deb file (like Apache, etc.) You can fix that by running this after:
sudo apt-get install -f
Also, I hope this project is an internal one, and not exposed to the internet. But I am sure you are aware of the dangers, right? ;)