In October 2024 I rewrote this guide. The updated version contains less information, but it simplified to 7 steps with limited downtime (unless your install is huge) and limited chance of failure.

Feel free to read the rest of this article if you like a broad knowledge of things before you start.

Updated 27th September 2020 to consider restart of all services where restarting just apache isn’t enough, and also to share choice when it comes to import first vs SSL first as you may lose permalinks. Thanks to Peter and Simon in the comments.

Updated 25th January 2021 to add an initial paragraph clarifying that you can’t ‘choose’ a PHP version on Lightsail and to further clarify that you must first check which version of PHP a new AWS Lightsail instance will be built with to confirm it will resolve the message being displayed in WordPress.

Updated 11th May 2021 to confirm that snapshots cannot be used to update the PHP version of a Lightsail Bitnami instance.

Updated 22nd September 2022 to add a link to a guide to check which PHP version you’ll get if you spin up a new Lightsail WordPress instance. Also added a note about WordPress supported PHP versions.

Updated 7th September 2023 to add a mention of the option to use Bitnami’s bncert tool to create an SSL certificate

NB: If you’re hoping for a way to click ‘update php’ or ‘use X version of PHP’ in Lightsail, it doesn’t (at time of writing) exist. This guidance will walk you though creating a new Lightsail instance with a newer version of PHP installed and moving everything over to it.

The AWS Lightsail service is great. Click a few buttons and you have a powerful VPS with WordPress up and running for only a few dollars a month. The Bitnami integration allows you to choose from a whole set of Stacks to include upon setup. The LAMP option allows a competent PHP developer to run almost anything on Lightsail.

But after a while running the Lightsail VPS the setup is going to get stale, and because Bitnami bundles everything up, it’s not recommended to go poking around with only a few parts of it.

That’s the challenge I was faced with. Logging into the WordPress admin console a message is displayed which is telling me WordPress would prefer a newer version of PHP please. My version was old and not receiving security updates.

I read a fair bit about my options, but after looking at the choices I decided the best thing was to do an export and import onto a new Lightsail instance.

A very quick and dirty way to export key and value pairs from web console of elastic beanstalk environments config page.

While viewing the elastic beanstalk config page containing the variable inputs paste the following into your browser console.

var strs = [], inputs = $('.properties-table input');
$.each(inputs, function(key, input){
  if(!((key+1)%2)){
    strs.push(inputs[(key-1)].value + ' = ' + inputs[key].value);
  }
})
console.log(strs.join("\n"));

When you set up an Apache or LAMP Lightsail instance on Amazon Web Services, the default document root is /home/bitnami/htdocs/

If you are migrating to Lightsail already use something other than htdocs as your root folder, for example public_html, then you might want to update this.

Although you could creating a new app on the server to hand it, here is a simpler option which leaves the default folders and setup in place:

In /opt/bitnami/apache2/conf/bitnami/bitnami.conf add your own document root to the end of every location that htdocs is mentioned.

Then

sudo chown -R bitnami:daemon /home/bitnami/htdocs/*
sudo chmod -R g+w /home/bitnami/htdocs
sudo /opt/bitnami/ctlscript.sh restart apache

And you should be good to go.