diff --git a/core/admin/mailu/internal/views/dovecot.py b/core/admin/mailu/internal/views/dovecot.py
index 2f5f68a4..0d56950b 100644
--- a/core/admin/mailu/internal/views/dovecot.py
+++ b/core/admin/mailu/internal/views/dovecot.py
@@ -33,6 +33,7 @@ def dovecot_quota(ns, user_email):
     user = models.User.query.get(user_email) or flask.abort(404)
     if ns == "storage":
         user.quota_bytes_used = flask.request.get_json()
+        user.dont_change_updated_at()
         models.db.session.commit()
     return flask.jsonify(None)
 
diff --git a/core/admin/mailu/internal/views/fetch.py b/core/admin/mailu/internal/views/fetch.py
index ccd3a159..1945b9c7 100644
--- a/core/admin/mailu/internal/views/fetch.py
+++ b/core/admin/mailu/internal/views/fetch.py
@@ -27,6 +27,7 @@ def fetch_done(fetch_id):
     fetch = models.Fetch.query.get(fetch_id) or flask.abort(404)
     fetch.last_check = datetime.datetime.now()
     fetch.error_message = str(flask.request.get_json())
+    fetch.dont_change_updated_at()
     models.db.session.add(fetch)
     models.db.session.commit()
     return ""
diff --git a/core/admin/mailu/models.py b/core/admin/mailu/models.py
index 70a9528f..0071bc77 100644
--- a/core/admin/mailu/models.py
+++ b/core/admin/mailu/models.py
@@ -25,6 +25,7 @@ from flask import current_app as app
 from sqlalchemy.ext import declarative
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.inspection import inspect
+from sqlalchemy.orm.attributes import flag_modified
 from werkzeug.utils import cached_property
 
 from mailu import dkim, utils
@@ -154,6 +155,10 @@ class Base(db.Model):
             self.__hashed = id(self) if primary is None else hash(primary)
         return self.__hashed
 
+    def dont_change_updated_at(self):
+        """ Mark updated_at as modified, but keep the old date when updating the model"""
+        flag_modified(self, 'updated_at')
+
 
 # Many-to-many association table for domain managers
 managers = db.Table('manager', Base.metadata,
diff --git a/towncrier/newsfragments/1363.bugfix b/towncrier/newsfragments/1363.bugfix
new file mode 100644
index 00000000..edb198d7
--- /dev/null
+++ b/towncrier/newsfragments/1363.bugfix
@@ -0,0 +1 @@
+Do not update the updated_at field of the User model when quota_bytes_used is updated
\ No newline at end of file