@derrabus Right after upgrading my application with the following Doctrine-related version bumps, I get an error :

Compile Error: Cannot declare class Doctrine\Common\EventManager, because the name is already in use

• Upgrading doctrine/common (3.4.2 => 3.4.3)
• Upgrading doctrine/event-manager (1.1.2 => 1.2.0)
• Upgrading doctrine/orm (2.13.2 => 2.13.3)
• Upgrading doctrine/persistence (2.5.4 => 2.5.5)

Am I missing something ? If I lock doctrine/event-manager to 1.1.2 and upgrade the rest, it works.

I don't know, but without a reproducer I cannot help you.

Also, please open a dedicated issue for this.