diff --git a/addons/account/models/account_move.py b/addons/account/models/account_move.py
index 377a85b191c..3f7124fca7a 100644
--- a/addons/account/models/account_move.py
+++ b/addons/account/models/account_move.py
@@ -3063,7 +3063,7 @@ class AccountMove(models.Model):
             'res_model': 'account.invoice.send',
             'view_mode': 'form',
             'context': {
-                'default_email_layout_xmlid': 'mail.mail_notification_paynow',
+                'default_email_layout_xmlid': 'mail.mail_notification_layout_with_responsible_signature',
                 'default_template_id': self.env.ref(self._get_mail_template()).id,
                 'mark_invoice_as_sent': True,
                 'active_model': 'account.move',
@@ -3099,7 +3099,7 @@ class AccountMove(models.Model):
             default_template_id=template and template.id or False,
             default_composition_mode='comment',
             mark_invoice_as_sent=True,
-            default_email_layout_xmlid="mail.mail_notification_paynow",
+            default_email_layout_xmlid="mail.mail_notification_layout_with_responsible_signature",
             model_description=self.with_context(lang=lang).type_name,
             force_email=True,
         )
@@ -3584,13 +3584,15 @@ class AccountMove(models.Model):
             message, msg_vals, model_description=model_description,
             force_email_company=force_email_company, force_email_lang=force_email_lang
         )
+        subtitles = [render_context['record'].name]
         if self.invoice_date_due:
-            render_context['subtitle'] = _('%(amount)s due\N{NO-BREAK SPACE}%(date)s',
+            subtitles.append(_('%(amount)s due\N{NO-BREAK SPACE}%(date)s',
                            amount=format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')),
                            date=format_date(self.env, self.invoice_date_due, date_format='short', lang_code=render_context.get('lang'))
-                          )
+                          ))
         else:
-            render_context['subtitle'] = format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang'))
+            subtitles.append(format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')))
+        render_context['subtitles'] = subtitles
         return render_context
 
     # -------------------------------------------------------------------------
diff --git a/addons/crm/models/crm_lead.py b/addons/crm/models/crm_lead.py
index 2586bceff1e..db4613877ab 100644
--- a/addons/crm/models/crm_lead.py
+++ b/addons/crm/models/crm_lead.py
@@ -16,6 +16,7 @@ from odoo.exceptions import UserError, AccessError
 from odoo.osv import expression
 from odoo.tools.translate import _
 from odoo.tools import date_utils, email_re, email_split, is_html_empty, groupby
+from odoo.tools.misc import get_lang
 
 from . import crm_stage
 
@@ -1792,6 +1793,17 @@ class Lead(models.Model):
             return self.env.ref('crm.mt_lead_lost')
         return super(Lead, self)._track_subtype(init_values)
 
+    def _notify_by_email_prepare_rendering_context(self, message, msg_vals=False, model_description=False,
+                                                   force_email_company=False, force_email_lang=False):
+        render_context = super()._notify_by_email_prepare_rendering_context(
+            message, msg_vals, model_description=model_description,
+            force_email_company=force_email_company, force_email_lang=force_email_lang
+        )
+        if self.date_deadline:
+            render_context['subtitles'].append(
+                _('Deadline: %s', self.date_deadline.strftime(get_lang(self.env).date_format)))
+        return render_context
+
     def _notify_get_recipients_groups(self, msg_vals=None):
         """ Handle salesman recipients that can convert leads into opportunities
         and set opportunities as won / lost. """
diff --git a/addons/mail/data/mail_templates_chatter.xml b/addons/mail/data/mail_templates_chatter.xml
index 3d86bdfe9ec..06007c72bb8 100644
--- a/addons/mail/data/mail_templates_chatter.xml
+++ b/addons/mail/data/mail_templates_chatter.xml
@@ -3,15 +3,10 @@
     <data>
         <!-- Discuss utility templates for notifications -->
         <template id="message_user_assigned">
-<p style="margin: 0px;">
-    <span>Dear <t t-esc="object.user_id.sudo().name"/>,</span><br />
+    <span>Dear <t t-esc="object.user_id.sudo().name"/>,</span>
+    <br/><br/>
     <span style="margin-top: 8px;">You have been assigned to the <t t-esc="model_description or 'document'"/> <t t-esc="object.display_name"/>.</span>
-</p>
-<p style="padding-top: 24px; padding-bottom: 16px;">
-    <a t-att-href="access_link" t-att-data-oe-model="object._name" t-att-data-oe-id="object.id" style="background-color:#875A7B; padding: 10px; text-decoration: none; color: #fff; border-radius: 5px;">
-            View <t t-esc="model_description or 'document'"/>
-    </a>
-</p>
+    <br/>
         </template>
 
         <template id="message_activity_done">
@@ -36,17 +31,18 @@
 
         <template id="message_activity_assigned">
 <div style="margin: 0px; padding: 0px; font-size: 13px;">
-    <span t-field="activity.create_uid.name"/> assigned you an activity <span t-field="activity.activity_type_id.name"/>
-    <t t-if="activity.summary">(<span t-field="activity.summary"/>)</t>
-    on <span t-field="activity.res_name"/>
-    to close for <span t-field="activity.date_deadline"/>.<br />
-    <p style="padding: 16px 0px 16px 0px;">
-        <a t-att-href="access_link" t-att-data-oe-model="activity.res_model" t-att-data-oe-id="activity.res_id"
-            style="background-color:#875A7B; padding: 8px 16px 8px 16px; text-decoration: none; color: #fff; border-radius: 5px;">
-            View <t t-esc="model_description or 'document'"/>
-        </a>
+    Dear <span t-field="activity.user_id.name"/>,
+    <br/><br/>
+    <p>
+        <span t-field="activity.create_uid.name"/> has just assigned you the following activity:
+        <ul>
+            <li>Document: "<t t-esc="activity.res_name"/>"
+                <t t-if="model_description"> (<t t-esc="model_description"/>)</t>
+            </li>
+            <li t-if="activity.summary">Summary: <span t-field="activity.summary"/></li>
+            <li>Deadline: <span t-field="activity.date_deadline"/></li>
+        </ul>
     </p>
-    <div t-if="activity.note" style="margin-top: 8px;" t-field="activity.note"/>
 </div>
         </template>
 
diff --git a/addons/mail/data/mail_templates_email_layouts.xml b/addons/mail/data/mail_templates_email_layouts.xml
index 9ec93330306..ac83d2c0dc4 100644
--- a/addons/mail/data/mail_templates_email_layouts.xml
+++ b/addons/mail/data/mail_templates_email_layouts.xml
@@ -1,13 +1,14 @@
 <?xml version="1.0" encoding="utf-8"?>
 <odoo>
     <data>
-        <template id="message_notification_email">
+        <template id="mail_notification_layout" name="Mail: mail notification layout template">
 <html t-att-lang="lang">
 <header>
     <meta http-equiv="Content-Type" content="text/html charset=UTF-8" />
 </header>
-<body>
-<t t-set="subtype_internal" t-value="subtype.internal"/>
+<body style="font-family:Verdana, Arial,sans-serif; color: #454748;">
+<t t-set="subtype_internal" t-value="subtype and subtype.internal"/>
+<!-- HEADER -->
 <t t-call="mail.notification_preview"/>
 <div style="max-width: 900px; width: 100%;">
 <div t-if="has_button_access" itemscope="itemscope" itemtype="http://schema.org/EmailMessage">
@@ -17,7 +18,7 @@
         <meta itemprop="name" t-att-content="button_access['title']"/>
     </div>
 </div>
-<div t-if="has_button_access or len(actions) &gt; 0 or not is_discussion"
+<div t-if="subtitles or has_button_access or len(actions) &gt; 0 or not is_discussion"
         summary="o_mail_notification" style="padding: 0px;">
     <table role="presentation" cellspacing="0" cellpadding="0" border="0" style="width: 100%; margin-top: 5px;">
         <tbody>
@@ -36,27 +37,31 @@
                     <table cellspacing="0" cellpadding="0" border="0">
                         <tbody>
                             <tr>
-                                <td t-if="has_button_access" style="border-radius: 3px; background: #875A7B; text-align: center; padding: 8px 12px;">
+                                <td t-if="has_button_access" style="border-radius: 3px; background: #875A7B; text-align: center; padding: 8px 12px 11px;">
                                     <a t-att-href="button_access['url']" style="font-size: 12px; color: #FFFFFF; text-decoration: none !important; font-weight: 400;">
                                         <t t-out="button_access['title']"/>
                                     </a>
                                 </td>
                                 <td t-if="has_button_access">&amp;nbsp;&amp;nbsp;</td>
 
+                                <td t-if="subtitles" style="font-size: 12px;">
+                                     <t t-foreach="subtitles" t-as="subtitle">
+                                        <span t-attf-style="{{ 'font-weight:bold;' if subtitle_first else '' }}"
+                                              t-out="subtitle"/>
+                                        <br t-if="not subtitle_last"/>
+                                    </t>
+                                </td>
+                                <td t-else=""><span style="font-weight:bold;" t-out="record_name"/><br/></td>
+                                <td>&amp;nbsp;&amp;nbsp;</td>
+
                                 <td t-if="actions">
                                     <t t-foreach="actions" t-as="action">
                                         |
-                                        <a t-att-href="action['url']" style="color: #875A7B; text-decoration:none !important;">
+                                        <a t-att-href="action['url']" style="font-size: 12px; color: #875A7B; text-decoration:none !important;">
                                             <t t-out="action['title']"/>
                                         </a>
                                     </t>
                                 </td>
-                                <td t-if="actions">&amp;nbsp;&amp;nbsp;</td>
-
-                                <td style="font-size: 12px;">
-                                    <span style="font-weight:bold;" t-out="record_name"/><br/>
-                                    <span t-if="not is_html_empty(subtitle)" t-out="subtitle"/>
-                                </td>
                             </tr>
                         </tbody>
                     </table>
@@ -66,7 +71,7 @@
                 <td valign="center">
                     <hr width="100%"
                         style="background-color:rgb(204,204,204);border:medium none;clear:both;display:block;font-size:0px;min-height:1px;line-height:0;margin: 10px 0px;"/>
-                    <p t-if="subtype_internal" style="background-color: #f2dede; padding: 5px; margin-bottom: 16px;">
+                    <p t-if="subtype_internal" style="background-color: #f2dede; padding: 5px; margin-bottom: 16px; font-size: 13px;">
                         <strong>Internal communication</strong>: Replying will post an internal note. Followers won't receive any email notification.
                     </p>
                 </td>
@@ -74,24 +79,30 @@
         </tbody>
     </table>
 </div>
-<div t-out="message.body"/>
+<!-- CONTENT -->
+<div t-out="message.body" style="font-size: 13px;"/>
 <ul t-if="tracking_values">
     <t t-foreach="tracking_values" t-as="tracking">
         <li><t t-out="tracking[0]"/>: <t t-out="tracking[1]"/> &#8594; <t t-out="tracking[2]"/></li>
     </t>
 </ul>
-<div t-if="email_add_signature and not is_html_empty(signature)" t-out="signature" style="font-size: 13px;"/>
-<p style="color: #555555; margin-top:32px;">
-    Sent
-    <span t-if="company.name">
-    by
-    <a t-if="website_url" t-att-href="website_url" style="text-decoration:none; color: #875A7B;">
-        <span t-out="company.name"/>
-    </a>
-    <span t-if="not website_url" t-out="company.name"/>
-    </span>
-    using
-    <a target="_blank" href="https://www.odoo.com?utm_source=db&amp;utm_medium=email" style="text-decoration:none; color: #875A7B;">Odoo</a>.
+<t class="o_signature">
+    <div t-if="email_add_signature and not is_html_empty(signature)" t-out="signature" style="font-size: 13px;"/>
+</t>
+<!-- FOOTER -->
+<div style="margin-top:32px;">
+    <hr width="100%" style="background-color:rgb(204,204,204);border:medium none;clear:both;display:block;font-size:0px;min-height:1px;line-height:0; margin: 16px 0px 4px 0px;"/>
+    <b t-out="company.name" style="font-size:11px;"/><br/>
+    <p style="color: #999999; margin-top:2px; font-size:11px;">
+        <t t-out="company.phone"/>
+        <t t-if="company.email and company.phone"> |</t>
+        <a t-if="company.email" t-att-href="'mailto:%s' % company.email" style="text-decoration:none; color: #999999;" t-out="company.email"/>
+        <t t-if="company.website and (company.phone or company.email)"> |</t>
+        <a t-if="company.website" t-att-href="'%s' % company.website" style="text-decoration:none; color: #999999;" t-out="company.website"/>
+    </p>
+</div>
+<p style="color: #555555; font-size:11px;">
+    Powered by <a target="_blank" href="https://www.odoo.com?utm_source=db&amp;utm_medium=email" style="color: #875A7B;">Odoo</a>
 </p>
 </div>
 </body></html>
@@ -168,112 +179,6 @@
 </html>
         </template>
 
-        <!-- Used mainly in conjunction of portal models (SO, PO, Invoices) although not mandatory -->
-        <template id="mail_notification_paynow" name="Mail: Pay Now mail notification template">
-<html t-att-lang="lang">
-<header>
-    <meta http-equiv="Content-Type" content="text/html charset=UTF-8" />
-</header>
-<body>
-<t t-set="subtype_internal" t-value="False"/>
-<t t-call="mail.notification_preview"/>
-<table role="presentation" border="0" cellpadding="0" cellspacing="0" style="background-color: #FFFFFF; font-family:Verdana, Arial,sans-serif; color: #454748; width: 100%; border-collapse:separate;"><tr><td>
-<table role="presentation" border="0" cellpadding="0" cellspacing="0" style="max-width:900px; width:100%; background-color: #FFFFFF; color: #454748; border-collapse:separate;">
-<tbody>
-    <!-- HEADER -->
-    <tr>
-        <td align="center">
-            <table role="presentation" border="0" cellpadding="0" cellspacing="5" width="100%" style="background-color: #FFFFFF; padding: 0; border-collapse:separate;">
-                <tr><td>
-                    <img t-att-src="'/logo.png?company=%s' % (company.id or 0)" height="48" style="padding: 0; margin: 0"  t-att-alt="'%s' % company.name"/>
-                </td></tr>
-                <tr><td>
-                    <hr width="100%" style="background-color:rgb(204,204,204);border:medium none;clear:both;display:block;font-size:0px;min-height:1px;line-height:0; margin:5px 0;"/>
-                </td></tr>
-                <tr><td valign="middle" style="white-space:nowrap;"><table cellspacing="0" cellpadding="0"><tr>
-                    <t t-if="has_button_access"><td>
-                        <table role="presentation" cellspacing="0" cellpadding="0" border="0">
-                            <tr><td style="border-radius: 3px; background: #875A7B; text-align: center; padding: 8px 12px;">
-                                <a t-att-href="button_access['url']"
-                                   style="border: 0; font-size: 12px; text-decoration: none !important; text-decoration: none; font-weight: 400; text-align: center; display: block;">
-                                    <span style="white-space:nowrap; color:#FFFFFF;" t-out="button_access['title']"></span>
-                                </a>
-                            </td></tr>
-                        </table></td><td width="7"></td><!--only inner cellspacing-->
-                    </t>
-                    <t t-if="not has_button_access and is_html_empty(subtitle)">
-                        <td>
-                            <span style="font-size: 10px;">Your <t t-out="model_description or 'document'"/></span>
-                            <br />
-                            <span style="font-size: 20px; font-weight: bold;">
-                                <t t-out="message.record_name and message.record_name.replace('/','-') or ''"/>
-                            </span>
-                        </td><td width="7"></td>
-                    </t>
-                    <t t-if="actions">
-                        <td>
-                            <t t-foreach="actions" t-as="action">
-                                |
-                                <a t-att-href="action['url']" style="color: #875A7B; text-decoration:none !important; text-decoration: none;">
-                                    <t t-out="action['title']"/>
-                                </a>
-                            </t>
-                        </td><td width="7"></td>
-                    </t>
-                    <t t-if="not is_html_empty(subtitle)">
-                        <td style="font-size: 12px;">
-                            <span style="font-weight:bold;" t-out="record.name"/><br/>
-                            <span t-out="subtitle"/>
-                        </td>
-                    </t>
-                </tr></table></td></tr>
-                <tr><td>
-                    <hr width="100%" style="background-color:rgb(204,204,204);border:medium none;clear:both;display:block;font-size:0px;min-height:1px;line-height:0; margin: 5px 0px;"/>
-                </td></tr>
-            </table>
-        </td>
-    </tr>
-    <!-- CONTENT -->
-    <tr>
-        <td style="padding-left: 5px;">
-            <t t-out="message.body"/>
-            <t t-if="email_add_signature and 'user_id' in record and record.user_id and not record.env.user._is_superuser() and not is_html_empty(record.user_id.sudo().signature)">
-                <div style="margin: 0px; padding: 0px; font-size:13px;">
-                    Best regards,
-                </div>
-                <div>&amp;nbsp;</div>
-                <div style="font-size: 13px;">
-                    <div t-out="record.user_id.sudo().signature"/>
-                </div>
-            </t>
-        </td>
-    </tr>
-    <!-- FOOTER -->
-    <tr>
-        <td style="padding-left: 5px; font-size:11px;">
-            <hr width="100%" style="background-color:rgb(204,204,204);border:medium none;clear:both;display:block;font-size:0px;min-height:1px;line-height:0; margin: 16px 0px 4px 0px;"/>
-            <b t-out="company.name"/><br/>
-            <div style="color: #999999; padding-top:2px">
-                <t t-out="company.phone"/>
-                <t t-if="company.email and company.phone"> |</t>
-                <a t-if="company.email" t-att-href="'mailto:%s' % company.email" style="text-decoration:none; color: #999999;" t-out="company.email"/>
-                <t t-if="company.website and (company.phone or company.email)"> |</t>
-                <a t-if="company.website" t-att-href="'%s' % company.website" style="text-decoration:none; color: #999999;" t-out="company.website"/>
-            </div>
-        </td>
-    </tr>
-    <!-- POWERED BY -->
-    <tr><td style="padding: 2px 0 0 5px; font-size:11px;">
-        Powered by <a target="_blank" href="https://www.odoo.com?utm_source=db&amp;utm_medium=email" style="color: #875A7B;">Odoo</a>
-    </td></tr>
-</tbody>
-</table>
-</td></tr>
-</table>
-</body>
-</html>
-        </template>
-
         <template id="notification_preview">
 <div style="display: none; max-height: 0px; overflow: hidden;">
     <t t-if="tracking_values">
@@ -286,5 +191,16 @@
     <t t-out="'&#847; &#8203; ' * 140"/>
 </div>
         </template>
+
+        <template id="mail_notification_layout_with_responsible_signature"
+                  name="Mail: mail notification layout with responsible signature (user_id of the record)"
+                  inherit_id="mail.mail_notification_layout" primary="True">
+            <xpath expr="//t[hasclass('o_signature')]" position="replace">
+                <t class="o_signature">
+                    <div t-if="email_add_signature and 'user_id' in record and record.user_id and not record.env.user._is_superuser() and not is_html_empty(record.user_id.sudo().signature)"
+                         t-out="record.user_id.sudo().signature" style="font-size: 13px;"/>
+                </t>
+            </xpath>
+        </template>
     </data>
 </odoo>
diff --git a/addons/mail/models/mail_activity.py b/addons/mail/models/mail_activity.py
index 2ce53932299..fd4d3a925e8 100644
--- a/addons/mail/models/mail_activity.py
+++ b/addons/mail/models/mail_activity.py
@@ -9,7 +9,8 @@ from dateutil.relativedelta import relativedelta
 
 from odoo import api, exceptions, fields, models, _, Command
 from odoo.osv import expression
-from odoo.tools.misc import clean_context
+from odoo.tools import is_html_empty
+from odoo.tools.misc import clean_context, get_lang
 
 
 class MailActivity(models.Model):
@@ -480,11 +481,11 @@ class MailActivity(models.Model):
             model_description = activity.env['ir.model']._get(activity.res_model).display_name
             body = activity.env['ir.qweb']._render(
                 'mail.message_activity_assigned',
-                dict(
-                    activity=activity,
-                    model_description=model_description,
-                    access_link=activity.env['mail.thread']._notify_get_action_link('view', model=activity.res_model, res_id=activity.res_id),
-                ),
+                {
+                    'activity': activity,
+                    'model_description': model_description,
+                    'is_html_empty': is_html_empty,
+                },
                 minimal_qcontext=True
             )
             record = activity.env[activity.res_model].browse(activity.res_id)
@@ -492,12 +493,14 @@ class MailActivity(models.Model):
                 record.message_notify(
                     partner_ids=activity.user_id.partner_id.ids,
                     body=body,
-                    subject=_('%(activity_name)s: %(summary)s assigned to you',
-                        activity_name=activity.res_name,
-                        summary=activity.summary or activity.activity_type_id.name),
                     record_name=activity.res_name,
                     model_description=model_description,
-                    email_layout_xmlid='mail.mail_notification_light',
+                    email_layout_xmlid='mail.mail_notification_layout',
+                    subject=_('"%(activity_name)s: %(summary)s" assigned to you',
+                              activity_name=activity.res_name,
+                              summary=activity.summary or activity.activity_type_id.name),
+                    subtitles=[_('Activity: %s', activity.activity_type_id.name),
+                               _('Deadline: %s', activity.date_deadline.strftime(get_lang(activity.env).date_format))]
                 )
 
     def action_done(self):
diff --git a/addons/mail/models/mail_template.py b/addons/mail/models/mail_template.py
index ca6500d9b2d..192357b7a40 100644
--- a/addons/mail/models/mail_template.py
+++ b/addons/mail/models/mail_template.py
@@ -319,7 +319,7 @@ class MailTemplate(models.Model):
                 'model_description': model.display_name,
                 'record': record,
                 'record_name': False,
-                'subtitle': False,
+                'subtitles': False,
                 # user / environment
                 'company': 'company_id' in record and record['company_id'] or self.env.company,
                 'email_add_signature': False,
diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index a0e84dfacb1..c5183a7fc53 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -2411,7 +2411,7 @@ class MailThread(models.AbstractModel):
                                 mail_auto_delete=True,  # mail.mail
                                 model_description=False, force_email_company=False, force_email_lang=False,  # rendering
                                 resend_existing=False, force_send=True, send_after_commit=True,  # email send
-                                **kwargs):
+                                subtitles=None, **kwargs):
         """ Method to send email linked to notified messages.
 
         :param message: ``mail.message`` record to notify;
@@ -2442,6 +2442,7 @@ class MailThread(models.AbstractModel):
         :param force_send: send emails directly instead of using queue;
         :param send_after_commit: if force_send, tells whether to send emails after
           the transaction has been committed using a post-commit hook;
+        :param subtitles: optional list that will be set as template value "subtitles"
         """
         partners_data = [r for r in recipients_data if r['notif'] == 'email']
         if not partners_data:
@@ -2460,9 +2461,11 @@ class MailThread(models.AbstractModel):
             force_email_company=force_email_company,
             force_email_lang=force_email_lang,
         ) # 10 queries
+        if subtitles:
+            template_values['subtitles'] = subtitles
 
         email_layout_xmlid = msg_vals.get('email_layout_xmlid') if msg_vals else message.email_layout_xmlid
-        template_xmlid = email_layout_xmlid if email_layout_xmlid else 'mail.message_notification_email'
+        template_xmlid = email_layout_xmlid if email_layout_xmlid else 'mail.mail_notification_layout'
         base_mail_values = self._notify_by_email_get_base_mail_values(message, additional_values={'auto_delete': mail_auto_delete})
 
         # Clean the context to get rid of residual default_* keys that could cause issues during
@@ -2649,7 +2652,7 @@ class MailThread(models.AbstractModel):
             'model_description': model_description,
             'record': self,
             'record_name': record_name,
-            'subtitle': False,
+            'subtitles': [record_name],
             # user / environment
             'company': company,
             'email_add_signature': email_add_signature,
@@ -3070,7 +3073,7 @@ class MailThread(models.AbstractModel):
                 body=assignation_msg,
                 partner_ids=partner_ids,
                 record_name=record.display_name,
-                email_layout_xmlid='mail.mail_notification_light',
+                email_layout_xmlid='mail.mail_notification_layout',
                 model_description=model_description,
             )
 
diff --git a/addons/project/data/mail_template_data.xml b/addons/project/data/mail_template_data.xml
index e524ff084b6..4decc2c808b 100644
--- a/addons/project/data/mail_template_data.xml
+++ b/addons/project/data/mail_template_data.xml
@@ -100,15 +100,10 @@
 
         <!-- You have been assigned email -->
         <template id="project_message_user_assigned">
-<p style="margin: 0px;">
-    <span>Dear <t t-esc="assignee_name"/>,</span><br />
+    <span>Dear <t t-esc="assignee_name"/>,</span>
+    <br/><br/>
     <span style="margin-top: 8px;">You have been assigned to the <t t-esc="model_description or 'document'"/> <t t-esc="object.display_name"/>.</span>
-</p>
-<p style="padding-top: 24px; padding-bottom: 16px;">
-    <a t-att-href="access_link" t-att-data-oe-model="object._name" t-att-data-oe-id="object.id" style="background-color:#875A7B; padding: 10px; text-decoration: none; color: #fff; border-radius: 5px;">
-            View <t t-esc="model_description or 'document'"/>
-    </a>
-</p>
+    <br/>
         </template>
     </data>
 </odoo>
diff --git a/addons/project/models/project.py b/addons/project/models/project.py
index 6f1ebf48d57..391ae1bf7c4 100644
--- a/addons/project/models/project.py
+++ b/addons/project/models/project.py
@@ -2045,8 +2045,6 @@ class Task(models.Model):
 
         result = super(Task, tasks).write(vals)
 
-        self._task_message_auto_subscribe_notify({task: task.user_ids - old_user_ids[task] - self.env.user for task in self})
-
         if 'user_ids' in vals:
             tasks._populate_missing_personal_stages()
 
@@ -2065,6 +2063,8 @@ class Task(models.Model):
             if task.display_project_id != task.project_id and not task.parent_id:
                 # We must make the display_project_id follow the project_id if no parent_id set
                 task.display_project_id = task.project_id
+
+        self._task_message_auto_subscribe_notify({task: task.user_ids - old_user_ids[task] - self.env.user for task in self})
         return result
 
     def update_date_end(self, stage_id):
@@ -2141,6 +2141,20 @@ class Task(models.Model):
     # Mail gateway
     # ---------------------------------------------------
 
+    def _notify_by_email_prepare_rendering_context(self, message, msg_vals=False, model_description=False,
+                                                   force_email_company=False, force_email_lang=False):
+        render_context = super()._notify_by_email_prepare_rendering_context(
+            message, msg_vals, model_description=model_description,
+            force_email_company=force_email_company, force_email_lang=force_email_lang
+        )
+        if self.date_deadline:
+            render_context['subtitles'].append(
+                _('Deadline: %s', self.date_deadline.strftime(get_lang(self.env).date_format)))
+        elif self.date_assign:
+            render_context['subtitles'].append(
+                _('Assigned On: %s', self.date_assign.strftime(get_lang(self.env).date_format)))
+        return render_context
+
     @api.model
     def _task_message_auto_subscribe_notify(self, users_per_task):
         # Utility method to send assignation notification upon writing/creation.
@@ -2165,7 +2179,7 @@ class Task(models.Model):
                     body=assignation_msg,
                     partner_ids=user.partner_id.ids,
                     record_name=task.display_name,
-                    email_layout_xmlid='mail.mail_notification_light',
+                    email_layout_xmlid='mail.mail_notification_layout',
                     model_description=task_model_description,
                 )
 
diff --git a/addons/purchase/models/purchase.py b/addons/purchase/models/purchase.py
index 199716d2cfb..a795a85d0d4 100644
--- a/addons/purchase/models/purchase.py
+++ b/addons/purchase/models/purchase.py
@@ -366,15 +366,17 @@ class PurchaseOrder(models.Model):
             message, msg_vals, model_description=model_description,
             force_email_company=force_email_company, force_email_lang=force_email_lang
         )
+        subtitles = [render_context['record'].name]
         # don't show price on RFQ mail
         if self.state not in ['draft', 'sent']:
             if self.date_order:
-                render_context['subtitle'] = _('%(amount)s due\N{NO-BREAK SPACE}%(date)s',
-                            amount=format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')),
-                            date=format_date(self.env, self.date_order, date_format='short', lang_code=render_context.get('lang'))
-                            )
+                subtitles.append(_('%(amount)s due\N{NO-BREAK SPACE}%(date)s',
+                                   amount=format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')),
+                                   date=format_date(self.env, self.date_order, date_format='short', lang_code=render_context.get('lang'))
+                                   ))
             else:
-                render_context['subtitle'] = format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang'))
+                subtitles.append(format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')))
+        render_context['subtitles'] = subtitles
         return render_context
 
     def _track_subtype(self, init_values):
@@ -421,7 +423,7 @@ class PurchaseOrder(models.Model):
             'default_use_template': bool(template_id),
             'default_template_id': template_id,
             'default_composition_mode': 'comment',
-            'default_email_layout_xmlid': "mail.mail_notification_paynow",
+            'default_email_layout_xmlid': "mail.mail_notification_layout_with_responsible_signature",
             'force_email': True,
             'mark_rfq_as_sent': True,
         })
@@ -745,7 +747,7 @@ class PurchaseOrder(models.Model):
                     if send_single:
                         return order._send_reminder_open_composer(template.id)
                     else:
-                        order.with_context(is_reminder=True).message_post_with_template(template.id, email_layout_xmlid="mail.mail_notification_paynow", composition_mode='comment')
+                        order.with_context(is_reminder=True).message_post_with_template(template.id, email_layout_xmlid="mail.mail_notification_layout_with_responsible_signature", composition_mode='comment')
 
     def send_reminder_preview(self):
         self.ensure_one()
@@ -758,7 +760,7 @@ class PurchaseOrder(models.Model):
                 self.id,
                 force_send=True,
                 raise_exception=False,
-                email_layout_xmlid="mail.mail_notification_paynow",
+                email_layout_xmlid="mail.mail_notification_layout_with_responsible_signature",
                 email_values={'email_to': self.env.user.email, 'recipient_ids': []},
             )
             return {'toast_message': escape(_("A sample email has been sent to %s.", self.env.user.email))}
@@ -778,7 +780,7 @@ class PurchaseOrder(models.Model):
             'default_use_template': bool(template_id),
             'default_template_id': template_id,
             'default_composition_mode': 'comment',
-            'default_email_layout_xmlid': "mail.mail_notification_paynow",
+            'default_email_layout_xmlid': "mail.mail_notification_layout_with_responsible_signature",
             'force_email': True,
             'mark_rfq_as_sent': True,
         })
diff --git a/addons/sale/models/payment_transaction.py b/addons/sale/models/payment_transaction.py
index af9d9a85a70..ef8f89e0634 100644
--- a/addons/sale/models/payment_transaction.py
+++ b/addons/sale/models/payment_transaction.py
@@ -132,7 +132,7 @@ class PaymentTransaction(models.Model):
             for invoice in invoice_to_send.with_user(SUPERUSER_ID):
                 invoice.message_post_with_template(
                     int(template_id),
-                    email_layout_xmlid='mail.mail_notification_paynow',
+                    email_layout_xmlid='mail.mail_notification_layout_with_responsible_signature',
                 )
 
     def _cron_send_invoice(self):
diff --git a/addons/sale/models/res_company.py b/addons/sale/models/res_company.py
index 44764a213e6..0bdf835dce1 100644
--- a/addons/sale/models/res_company.py
+++ b/addons/sale/models/res_company.py
@@ -94,7 +94,7 @@ class ResCompany(models.Model):
         message_composer = self.env['mail.compose.message'].with_context(
             default_use_template=bool(template),
             mark_so_as_sent=True,
-            default_email_layout_xmlid='mail.mail_notification_paynow',
+            default_email_layout_xmlid='mail.mail_notification_layout_with_responsible_signature',
             proforma=self.env.context.get('proforma', False),
             force_email=True, mail_notify_author=True
         ).create({
diff --git a/addons/sale/models/sale_order.py b/addons/sale/models/sale_order.py
index 5189ac2d572..2a26a17dbb8 100644
--- a/addons/sale/models/sale_order.py
+++ b/addons/sale/models/sale_order.py
@@ -728,7 +728,7 @@ class SaleOrder(models.Model):
             'default_template_id': mail_template.id if mail_template else None,
             'default_composition_mode': 'comment',
             'mark_so_as_sent': True,
-            'default_email_layout_xmlid': 'mail.mail_notification_paynow',
+            'default_email_layout_xmlid': "mail.mail_notification_layout_with_responsible_signature",
             'proforma': self.env.context.get('proforma', False),
             'force_email': True,
             'model_description': self.with_context(lang=lang).type_name,
@@ -837,7 +837,7 @@ class SaleOrder(models.Model):
             self.with_context(force_send=True).message_post_with_template(
                 mail_template.id,
                 composition_mode='comment',
-                email_layout_xmlid='mail.mail_notification_paynow',
+                email_layout_xmlid='mail.mail_notification_layout_with_responsible_signature',
             )
 
     def action_done(self):
@@ -873,7 +873,7 @@ class SaleOrder(models.Model):
                 'default_template_id': template_id,
                 'default_order_id': self.id,
                 'mark_so_as_canceled': True,
-                'default_email_layout_xmlid': 'mail.mail_notification_paynow',
+                'default_email_layout_xmlid': "mail.mail_notification_layout_with_responsible_signature",
                 'model_description': self.with_context(lang=lang).type_name,
             }
             return {
@@ -1231,15 +1231,15 @@ class SaleOrder(models.Model):
             message, msg_vals, model_description=model_description,
             force_email_company=force_email_company, force_email_lang=force_email_lang
         )
+        subtitles = [render_context['record'].name]
         if self.validity_date:
-            render_context['subtitle'] = _(
-                u'%(amount)s due\N{NO-BREAK SPACE}%(date)s',
-                amount=format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')),
-                date=format_date(self.env, self.validity_date, date_format='short', lang_code=render_context.get('lang'))
-            )
+            subtitles.append(_(u'%(amount)s due\N{NO-BREAK SPACE}%(date)s',
+                           amount=format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')),
+                           date=format_date(self.env, self.validity_date, date_format='short', lang_code=render_context.get('lang'))
+                          ))
         else:
-            render_context['subtitle'] = format_amount(
-                self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang'))
+            subtitles.append(format_amount(self.env, self.amount_total, self.currency_id, lang_code=render_context.get('lang')))
+        render_context['subtitles'] = subtitles
         return render_context
 
     def _sms_get_number_fields(self):
diff --git a/addons/test_mail/tests/test_mail_activity.py b/addons/test_mail/tests/test_mail_activity.py
index a80d0592cc5..29ac717601f 100644
--- a/addons/test_mail/tests/test_mail_activity.py
+++ b/addons/test_mail/tests/test_mail_activity.py
@@ -176,7 +176,7 @@ class TestActivityFlow(TestActivityCommon):
         rec = self.test_record.with_user(self.user_employee)
         with self.assertSinglePostNotifications(
                 [{'partner': self.partner_admin, 'type': 'email'}],
-                message_info={'content': 'assigned you an activity', 'subtype': 'mail.mt_note', 'message_type': 'user_notification'}):
+                message_info={'content': 'assigned you the following activity', 'subtype': 'mail.mt_note', 'message_type': 'user_notification'}):
             activity = rec.activity_schedule(
                 'test_mail.mail_act_test_todo',
                 user_id=self.user_admin.id)
diff --git a/addons/test_mail/tests/test_message_post.py b/addons/test_mail/tests/test_message_post.py
index df7b969e82c..102191babb5 100644
--- a/addons/test_mail/tests/test_message_post.py
+++ b/addons/test_mail/tests/test_message_post.py
@@ -86,9 +86,9 @@ class TestMailNotifyAPI(TestMessagePostCommon):
         test_message = self.env['mail.message'].browse(self.test_message.ids)
 
         recipients_data = self._generate_notify_recipients(self.partner_1 + self.partner_2 + self.partner_employee)
-        for email_xmlid in ['mail.message_notification_email',
-                            'mail.mail_notification_light',
-                            'mail.mail_notification_paynow']:
+        for email_xmlid in ['mail.mail_notification_light',
+                            'mail.mail_notification_layout',
+                            'mail.mail_notification_layout_with_responsible_signature']:
             test_message.sudo().notification_ids.unlink()  # otherwise partner/message constraint fails
             test_message.write({'email_layout_xmlid': email_xmlid})
             with self.mock_mail_gateway():
@@ -118,14 +118,14 @@ class TestMailNotifyAPI(TestMessagePostCommon):
 
         signature = self.env.user.signature
 
-        template = self.env.ref('mail.mail_notification_paynow', raise_if_not_found=True).sudo()
+        template = self.env.ref('mail.mail_notification_layout_with_responsible_signature', raise_if_not_found=True).sudo()
         self.assertIn("record.user_id.sudo().signature", template.arch)
 
         with self.mock_mail_gateway():
             test_track.message_post(
                 body="Test body",
                 email_add_signature=True,
-                email_layout_xmlid="mail.mail_notification_paynow",
+                email_layout_xmlid="mail.mail_notification_layout_with_responsible_signature",
                 mail_auto_delete=False,
                 partner_ids=[self.partner_1.id, self.partner_2.id],
             )
@@ -137,7 +137,7 @@ class TestMailNotifyAPI(TestMessagePostCommon):
             test_track.message_post(
                 body="Test body",
                 email_add_signature=False,
-                email_layout_xmlid="mail.mail_notification_paynow",
+                email_layout_xmlid="mail.mail_notification_layout_with_responsible_signature",
                 mail_auto_delete=False,
                 partner_ids=[self.partner_1.id, self.partner_2.id],
             )
diff --git a/addons/test_mail/tests/test_performance.py b/addons/test_mail/tests/test_performance.py
index ad499e32a2d..a4f74b4ba6f 100644
--- a/addons/test_mail/tests/test_performance.py
+++ b/addons/test_mail/tests/test_performance.py
@@ -522,7 +522,7 @@ class TestMailAPIPerformance(BaseMailPerformance):
     def test_message_assignation_email(self):
         self.user_test.write({'notification_type': 'email'})
         record = self.env['mail.test.track'].create({'name': 'Test'})
-        with self.assertQueryCount(__system__=27, employee=28):
+        with self.assertQueryCount(__system__=28, employee=29):
             record.write({
                 'user_id': self.user_test.id,
             })
@@ -850,7 +850,7 @@ class TestMailComplexPerformance(BaseMailPerformance):
         })
         rec1 = rec.with_context(active_test=False)      # to see inactive records
         self.assertEqual(rec1.message_partner_ids, self.partners | self.env.user.partner_id)
-        with self.assertQueryCount(__system__=24, employee=25):
+        with self.assertQueryCount(__system__=25, employee=26):
             rec.write({'user_id': self.user_portal.id})
         self.assertEqual(rec1.message_partner_ids, self.partners | self.env.user.partner_id | self.user_portal.partner_id)
         # write tracking message
@@ -870,7 +870,7 @@ class TestMailComplexPerformance(BaseMailPerformance):
         customer_id = self.customer.id
         user_id = self.user_portal.id
 
-        with self.assertQueryCount(__system__=56, employee=57):  # tm 56/57
+        with self.assertQueryCount(__system__=57, employee=58):  # tm 57/58
             rec = self.env['mail.test.ticket'].create({
                 'name': 'Test',
                 'container_id': container_id,
diff --git a/addons/website_sale/models/sale_order.py b/addons/website_sale/models/sale_order.py
index 2c4898ed80f..70601c5d135 100644
--- a/addons/website_sale/models/sale_order.py
+++ b/addons/website_sale/models/sale_order.py
@@ -345,7 +345,7 @@ class SaleOrder(models.Model):
             'target': 'new',
             'context': {
                 'default_composition_mode': 'mass_mail' if len(self.ids) > 1 else 'comment',
-                'default_email_layout_xmlid': 'mail.mail_notification_paynow',
+                'default_email_layout_xmlid': 'mail.mail_notification_layout_with_responsible_signature',
                 'default_res_id': self.ids[0],
                 'default_model': 'sale.order',
                 'default_use_template': bool(template_id),