diff --git a/addons/im_livechat/models/res_users.py b/addons/im_livechat/models/res_users.py
index 96ca99ee741..9de83ef8928 100644
--- a/addons/im_livechat/models/res_users.py
+++ b/addons/im_livechat/models/res_users.py
@@ -18,6 +18,10 @@ class Users(models.Model):
     def SELF_READABLE_FIELDS(self):
         return super().SELF_READABLE_FIELDS + ['livechat_username', 'livechat_lang_ids', 'has_access_livechat']
 
+    @property
+    def SELF_WRITEABLE_FIELDS(self):
+        return super().SELF_WRITEABLE_FIELDS + ['livechat_username', 'livechat_lang_ids']
+
     @api.depends('res_users_settings_id.livechat_username')
     def _compute_livechat_username(self):
         for user in self:
diff --git a/addons/im_livechat/tests/test_message.py b/addons/im_livechat/tests/test_message.py
index daef9d8e33d..f9c1e937859 100644
--- a/addons/im_livechat/tests/test_message.py
+++ b/addons/im_livechat/tests/test_message.py
@@ -4,6 +4,7 @@
 from markupsafe import Markup
 
 from odoo import Command
+from odoo.exceptions import AccessError
 from odoo.tests.common import users, tagged, HttpCase
 
 
@@ -25,6 +26,19 @@ class TestImLivechatMessage(HttpCase):
             {'name': 'test1', 'login': 'test1', 'password': self.password, 'email': 'test1@example.com', 'livechat_username': 'chuck'},
         ])
 
+    def test_update_username(self):
+        user = self.env['res.users'].create({
+            'name': 'User',
+            'login': 'User',
+            'password': self.password,
+            'email': 'user@example.com',
+            'livechat_username': 'edit me'
+        })
+        with self.assertRaises(AccessError):
+            self.env['res.users'].with_user(user).check_access_rights('write')
+        user.with_user(user).livechat_username = 'New username'
+        self.assertEqual(user.livechat_username, 'New username')
+
     @users('emp')
     def test_message_format(self):
         im_livechat_channel = self.env['im_livechat.channel'].sudo().create({'name': 'support', 'user_ids': [Command.link(self.users[0].id)]})
diff --git a/odoo/addons/base/models/res_lang.py b/odoo/addons/base/models/res_lang.py
index 0ebfd61f430..87b84c043da 100644
--- a/odoo/addons/base/models/res_lang.py
+++ b/odoo/addons/base/models/res_lang.py
@@ -21,6 +21,7 @@ class Lang(models.Model):
     _name = "res.lang"
     _description = "Languages"
     _order = "active desc,name"
+    _allow_sudo_commands = False
 
     _disallowed_datetime_patterns = list(tools.DATETIME_FORMATS_MAP)
     _disallowed_datetime_patterns.remove('%y') # this one is in fact allowed, just not good practice