diff --git a/addons/mail/models/mail_mail.py b/addons/mail/models/mail_mail.py
index ff25c60f04a..0c374d18ad8 100644
--- a/addons/mail/models/mail_mail.py
+++ b/addons/mail/models/mail_mail.py
@@ -63,7 +63,18 @@ class MailMail(models.Model):
             values['notification'] = True
         if not values.get('mail_message_id'):
             self = self.with_context(message_create_from_mail_mail=True)
-        return super(MailMail, self).create(values)
+        new_mail = super(MailMail, self).create(values)
+        if values.get('attachment_ids'):
+            new_mail.attachment_ids.check(mode='read')
+        return new_mail
+
+    @api.multi
+    def write(self, vals):
+        res = super(MailMail, self).write(vals)
+        if vals.get('attachment_ids'):
+            for mail in self:
+                mail.attachment_ids.check(mode='read')
+        return res
 
     @api.multi
     def unlink(self):
diff --git a/addons/mail/models/mail_message.py b/addons/mail/models/mail_message.py
index 3716cd4e6f3..c3b351264d3 100644
--- a/addons/mail/models/mail_message.py
+++ b/addons/mail/models/mail_message.py
@@ -740,6 +740,10 @@ class Message(models.Model):
         # delegate creation of tracking after the create as sudo to avoid access rights issues
         tracking_values_cmd = values.pop('tracking_value_ids', False)
         message = super(Message, self).create(values)
+
+        if values.get('attachment_ids'):
+            message.attachment_ids.check(mode='read')
+
         if tracking_values_cmd:
             message.sudo().write({'tracking_value_ids': tracking_values_cmd})
 
@@ -762,6 +766,9 @@ class Message(models.Model):
         if 'model' in vals or 'res_id' in vals:
             self._invalidate_documents()
         res = super(Message, self).write(vals)
+        if vals.get('attachment_ids'):
+            for mail in self:
+                mail.attachment_ids.check(mode='read')
         self._invalidate_documents()
         return res
 
diff --git a/addons/mail/wizard/invite.py b/addons/mail/wizard/invite.py
index acb89641f75..3fee1d78eac 100644
--- a/addons/mail/wizard/invite.py
+++ b/addons/mail/wizard/invite.py
@@ -1,6 +1,9 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from lxml import etree
+from lxml.html import builder as html
+
 from odoo import _, api, fields, models
 
 
@@ -12,18 +15,27 @@ class Invite(models.TransientModel):
     @api.model
     def default_get(self, fields):
         result = super(Invite, self).default_get(fields)
+        if self._context.get('mail_invite_follower_channel_only'):
+            result['send_mail'] = False
+        if 'message' not in fields:
+            return result
+
         user_name = self.env.user.name_get()[0][1]
         model = result.get('res_model')
         res_id = result.get('res_id')
-        if self._context.get('mail_invite_follower_channel_only'):
-            result['send_mail'] = False
-        if 'message' in fields and model and res_id:
-            model_name = self.env['ir.model']._get(model).display_name
-            document_name = self.env[model].browse(res_id).name_get()[0][1]
-            message = _('<div><p>Hello,</p><p>%s invited you to follow %s document: %s.</p></div>') % (user_name, model_name, document_name)
-            result['message'] = message
-        elif 'message' in fields:
-            result['message'] = _('<div><p>Hello,</p><p>%s invited you to follow a new document.</p></div>') % user_name
+        if model and res_id:
+            document = self.env['ir.model']._get(model).display_name
+            title = self.env[model].browse(res_id).display_name
+            msg_fmt = _('%(user_name)s invited you to follow %(document)s document: %(title)s')
+        else:
+            msg_fmt = _('%(user_name)s invited you to follow a new document')
+
+        text = msg_fmt % locals()
+        message = html.DIV(
+            html.P(_('Hello,')),
+            html.P(text)
+        )
+        result['message'] = etree.tostring(message)
         return result
 
     res_model = fields.Char('Related Document Model', required=True, index=True, help='Model of the followed resource')
diff --git a/odoo/addons/base/ir/ir_translation.py b/odoo/addons/base/ir/ir_translation.py
index 2d013121a5f..072fb002fa6 100644
--- a/odoo/addons/base/ir/ir_translation.py
+++ b/odoo/addons/base/ir/ir_translation.py
@@ -464,15 +464,15 @@ class IrTranslation(models.Model):
         if not callable(field.translate):
             return
 
-        trans = self.env['ir.translation']
-        outdated = trans
-        discarded = trans
+        Translation = self.env['ir.translation']
+        outdated = Translation
+        discarded = Translation
 
         for record in records:
             # get field value and terms to translate
             value = record[field.name]
             terms = set(field.get_trans_terms(value))
-            record_trans = trans.search([
+            translations = Translation.search([
                 ('type', '=', 'model'),
                 ('name', '=', "%s,%s" % (field.model_name, field.name)),
                 ('res_id', '=', record.id),
@@ -480,25 +480,32 @@ class IrTranslation(models.Model):
 
             if not terms:
                 # discard all translations for that field
-                discarded += record_trans
+                discarded += translations
                 continue
 
-            # remap existing translations on terms when possible
-            trans_src = record_trans.mapped('src')
-            for trans in record_trans:
-                if trans.src == trans.value:
-                    discarded += trans
-                elif trans.src not in terms:
-                    matches = get_close_matches(trans.src, terms, 1, 0.9)
-                    if matches:
-                        if matches[0] in trans_src:
-                            # there is already a translation for this term; discard this one
-                            discarded += trans
-                        else:
-                            trans.write({'src': matches[0], 'state': trans.state})
-                            trans_src.append(matches[0])  # avoid reuse of term
-                    else:
-                        outdated += trans
+            # remap existing translations on terms when possible; each term
+            # should be translated at most once per language
+            done = set()                # {(src, lang), ...}
+            translations_to_match = []
+
+            for translation in translations:
+                if translation.src == translation.value:
+                    discarded += translation
+                elif translation.src in terms:
+                    done.add((translation.src, translation.lang))
+                else:
+                    translations_to_match.append(translation)
+
+            for translation in translations_to_match:
+                matches = get_close_matches(translation.src, terms, 1, 0.9)
+                src = matches[0] if matches else None
+                if not src:
+                    outdated += translation
+                elif (src, translation.lang) in done:
+                    discarded += translation
+                else:
+                    translation.write({'src': src, 'state': translation.state})
+                    done.add((src, translation.lang))
 
         # process outdated and discarded translations
         outdated.write({'state': 'to_translate'})
diff --git a/odoo/addons/base/tests/test_translate.py b/odoo/addons/base/tests/test_translate.py
index 328906c89c2..0c4e9c95cda 100644
--- a/odoo/addons/base/tests/test_translate.py
+++ b/odoo/addons/base/tests/test_translate.py
@@ -275,30 +275,36 @@ class TestTranslation(TransactionCase):
 class TestXMLTranslation(TransactionCase):
     def setUp(self):
         super(TestXMLTranslation, self).setUp()
-        self.env['ir.translation'].load_module_terms(['base'], ['fr_FR'])
+        self.env['ir.translation'].load_module_terms(['base'], ['fr_FR', 'nl_NL'])
+
+    def create_view(self, archf, terms, **kwargs):
+        view = self.env['ir.ui.view'].create({
+            'name': 'test',
+            'model': 'res.partner',
+            'arch': archf % terms,
+        })
+        for lang, trans_terms in kwargs.items():
+            for src, val in zip(terms, trans_terms):
+                self.env['ir.translation'].create({
+                    'type': 'model',
+                    'name': 'ir.ui.view,arch_db',
+                    'lang': lang,
+                    'res_id': view.id,
+                    'src': src,
+                    'value': val,
+                    'state': 'translated',
+                })
+        return view
 
     def test_copy(self):
         """ Create a simple view, fill in translations, and copy it. """
-        env_en = self.env(context={})
-        env_fr = self.env(context={'lang': 'fr_FR'})
-
         archf = '<form string="%s"><div>%s</div><div>%s</div></form>'
         terms_en = ('Knife', 'Fork', 'Spoon')
         terms_fr = ('Couteau', 'Fourchette', 'Cuiller')
-        view0 = self.env['ir.ui.view'].create({
-            'name': 'test',
-            'model': 'res.partner',
-            'arch': archf % terms_en,
-        })
-        for src, value in zip(terms_en, terms_fr):
-            self.env['ir.translation'].create({
-                'type': 'model',
-                'name': 'ir.ui.view,arch_db',
-                'lang': 'fr_FR',
-                'res_id': view0.id,
-                'src': src,
-                'value': value,
-            })
+        view0 = self.create_view(archf, terms_en, fr_FR=terms_fr)
+
+        env_en = self.env(context={})
+        env_fr = self.env(context={'lang': 'fr_FR'})
 
         # check translated field
         self.assertEqual(view0.with_env(env_en).arch_db, archf % terms_en)
@@ -325,17 +331,29 @@ class TestXMLTranslation(TransactionCase):
         archf = '<form string="%s"><div>%s</div><div>%s</div></form>'
         terms_en = ('Knife', 'Fork', 'Spoon')
         terms_fr = (' Couteau', 'Fourchette ', ' Cuiller ')
-        view0 = self.env['ir.ui.view'].create({
-            'name': 'test',
-            'model': 'res.partner',
-            'arch': archf % terms_en,
-        })
-        for src, value in zip(terms_en, terms_fr):
-            self.env['ir.translation'].create({
-                'type': 'model',
-                'name': 'ir.ui.view,arch_db',
-                'lang': 'fr_FR',
-                'res_id': view0.id,
-                'src': src,
-                'value': value,
-            })
+        self.create_view(archf, terms_en, fr_FR=terms_fr)
+
+    def test_sync(self):
+        """ Check translations after minor change in source terms. """
+        archf = '<form string="X">%s</form>'
+        terms_en = ('Bread and cheeze',)
+        terms_fr = ('Pain et fromage',)
+        terms_nl = ('Brood and kaas',)
+        view = self.create_view(archf, terms_en, fr_FR=terms_fr, nl_NL=terms_nl)
+
+        env_en = self.env(context={})
+        env_fr = self.env(context={'lang': 'fr_FR'})
+        env_nl = self.env(context={'lang': 'nl_NL'})
+
+        self.assertEqual(view.with_env(env_en).arch_db, archf % terms_en)
+        self.assertEqual(view.with_env(env_fr).arch_db, archf % terms_fr)
+        self.assertEqual(view.with_env(env_nl).arch_db, archf % terms_nl)
+
+        # modify source term in view (fixed type in 'cheeze')
+        terms_en = ('Bread and cheese',)
+        view.write({'arch_db': archf % terms_en})
+
+        # check whether translations have been synchronized
+        self.assertEqual(view.with_env(env_en).arch_db, archf % terms_en)
+        self.assertEqual(view.with_env(env_fr).arch_db, archf % terms_fr)
+        self.assertEqual(view.with_env(env_nl).arch_db, archf % terms_nl)