I have a site that has failed PCI compliance due to an older version of PHP. I need to upgrade the PHP install but need to know if Expresso Store v2.5.1 is compatible with PHP 7?
Thanks for any help.
There's no mention of PHP 7 in Expresso Store's release notes and no specific mention of it in their installation guide, so one would have to take the assumption that they have not specifically tested on PHP 7 yet.
In fact, v2.5.1 was released in May 2015, 6 months before the public release of PHP 7, so it's very unlikely it has been specifically tested or updated to ensure PHP 7 compatibility.
Having said that, it's likely everything should still just work. PHP have specifically gone to lengths to 'make migration as painless as possible' - see the migration guide here for more details.
I would probably feel comfortable upgrading the version of PHP, however of course you must do this on a test server rather than to your live site. Make sure error reporting is on so you can see notice of any newly deprecated functions (there's not a lot) that are being used, and test your site thoroughly. Contact Expresso or one of their listed professionals if you have any major issues that need resolution.