We generally support every PHP version which is officially supported. Some discrepancy with the officially supported and Servebolt supported versions are expected. We for example can’t support newer versions when they come out right away. This is because we rigorously test new versions to be secure and bug free with our infrastructure. Additionally we also might support older versions longer than what is officially supported.
Our recommendation is to always run the most modern stable version of PHP that your application supports. It is almost always faster, more secure and better maintained. It will also give your application the longest possible potential life, as opposed to choosing tech that is soon to be discontinued.
Changing PHP version
As of this writing, changing PHP versions needs a full site migration. This is because only one PHP version can exist per Bolt, since PHP is server specific.
To update the PHP version for your site, you first have to create a new Bolt with your new desired version. Copy all your files and database(s) over and test to see if anything breaks. Changing between major PHP versions are prone to break your site, so we recommend you to test thoroughly. If everything works as expected, do another live migration. We recommend you to set your site in maintenance so no new orders / signups etc. gets generated whilst the data transfer ensues. Upgrade the new Bolt to a paid plan if not done already, add your domain and update your DNS with the new server IP or hostname. You can now alternatively cancel your old Bolt.
This is just a fresh reminder with an overview over the whole process. If you need more detailed explanation for each step, please check out, How to upgrade the PHP version of your Bolt.
Contact our Support chat should you need further assistance with PHP upgrades and downgrades.