Important: #81868 - "Optimize autoloader" is no longer forced in composer.json¶
The option "optimize autoloader" (in config section of TYPO3's own composer.json) forced composer to create optimized autoloader files.
This improves speed but had three disadvantages:
creating optimized autoloader may take much longer
new namespaces (folders) during development require an additional
no possibility existing to deactivate optimized autoloader from CLI, once it's set in composer.json config section
The option was removed from TYPO3's own composer.json, so deployment servers using that need to call composer install with the -o flag, in order to enable the optimized autoloader.
This change only affects users that are using a non-composer installation but doing a composer install in TYPO3's root folder - if you are using your own composer.json you won't be affected.