First of all, thank you so much for your message.

Yes it is exactly what I want, I want to send e-mail to my customers in order to inform about maintenance.

- Ok, so if I understand what you said, it is necessary to develop our own plugin for OTRS if we want to do that.

or

- Show a message for my customers on the login page of the OTRS platform.

Is it true ?

Thanks again.

Regards,

Romain