Symfony 3.0 migration PHP 5.5 to PHP 7.1 : "A PHP accelerator should be installed > Install and/or enable a PHP accelerator (highly recommended)"?
Here is the solution, 2 things I needed to do:
1st: It needs indeed opcache.
In the php.ini, moreover than the settings that are instructed to do in symfony documentation and php manual. I had forgotten to add the extension to use in the php.ini:
zend_extension="[your path to php7]\php7\ext\php_opcache.dll"
(well it is in the php manual documentation here)
2nd: On symfony side, I had to update the following settings in [project path]\composer.json to make sure Symfony uses PHP7:
{ "require": { "php": ">=7.1.1", .... }, .... "config": { "platform": { "php": "7.1.1" } },}