eronn questions

• Error during migration from npm to yarn - The engine "node" is incompatible with this module
• unserialize() Please specify classes allowed for unserialization in 2nd argument
• Fullcalendar header buttons not responsive?
• Symfony 5 - Semaphore extension (sysvsem) is required
• A circular reference has been detected when serializing the object of class "App\Entity\User" (configured limit: 1)
• Symfony 4 - no such service exists for ObjectManager after composer update

eronn answers