<?xml version="1.0" encoding="utf-8" ?>
<odoo>

    <record id="email_compose_message_wizard_form" model="ir.ui.view">
        <field name="model">mail.compose.message</field>
        <field name="inherit_id" ref="mail.email_compose_message_wizard_form" />
        <field name="arch" type="xml">
            <xpath expr="//span[@name='document_followers_text']" position="before">
                <field
                    name="notify_followers"
                    attrs="{'invisible': [('composition_mode', '=', 'mass_mail')]}"
                />
            </xpath>
            <xpath expr="//span[@name='document_followers_text']" position="after">
                <span
                    name="no_followers_text"
                    attrs="{'invisible': [('notify_followers', '=', True)]}"
                    style="color: red;"
                > - Warning : Followers will not be notified but they can access the notification directly from the document (if they are allowed to)</span>
            </xpath>
        </field>
    </record>

</odoo>