Outdated TYPO3 Version
This documentation refers to an outdated TYPO3 version - either select a supported version or make sure to use a TYPO3 Extended Long Term Support (ELTS) version to continue getting security updates.
A good communication between several roles is essential to clarify responsibilities and to coordinate the next steps when updates are required, an attacked site needs to be restored or other security- related actions need to be done as soon as possible.
A central point of contact, for example a person or a team responsible for coordinating these actions, is generally a good idea. This also lets others (e.g. integrators, editors, end-users) know, to whom they can report issues.