question : disable email

[viisauksena]

is it even possible to run engelsystem without email , especially without enforced email at registration?

[MyIgel]

The Engelsystem is not designed to not have the email address but it should be possible to patch it in a way that it is not required.
Some further consideration should be done here for how users could reset their passwords and handling when trying to send mails / corresponding settings when you want to modify your instance to suit that need.