diff --git a/modoboa/pdfcredentials/api/v2/views.py b/modoboa/pdfcredentials/api/v2/views.py
index 08044981d..d92955ac4 100644
--- a/modoboa/pdfcredentials/api/v2/views.py
+++ b/modoboa/pdfcredentials/api/v2/views.py
@@ -12,6 +12,8 @@ from modoboa.admin.models import Domain
 
 from .serializers import GetAccountCredentialsSerializer
 
+from ...lib import rfc_6266_content_disposition
+
 
 class PDFCredentialView(APIView):
 
@@ -38,5 +40,5 @@ class PDFCredentialView(APIView):
         resp = HttpResponse(content)
         resp["Content-Type"] = "application/pdf"
         resp["Content-Length"] = len(content)
-        resp["Content-Disposition"] = f"attachment; filename={fname};"
+        resp["Content-Disposition"] = rfc_6266_content_disposition(fname)
         return resp
diff --git a/modoboa/pdfcredentials/lib.py b/modoboa/pdfcredentials/lib.py
index 6817f0479..69e3d6002 100644
--- a/modoboa/pdfcredentials/lib.py
+++ b/modoboa/pdfcredentials/lib.py
@@ -7,6 +7,8 @@ import struct
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
 from cryptography.hazmat.backends import default_backend
 
+from urllib.parse import quote
+
 from django.conf import settings
 from django.utils.encoding import force_bytes, smart_bytes
 from django.utils.translation import ugettext as _
@@ -105,3 +107,16 @@ def get_document_logo():
     if not os.path.isfile(logo):
         return None
     return logo
+
+
+def rfc_6266_content_disposition(filename):
+    """Copied from upcoming django 4.2. TBR on release."""
+    # TODO : remove me when updating to django 4.2
+    try:
+        filename.encode("ascii")
+        file_expr = 'filename="{}"'.format(
+            filename.replace("\\", "\\\\").replace('"', r"\"")
+        )
+    except UnicodeEncodeError:
+        file_expr = "filename*=utf-8''{}".format(quote(filename))
+    return f"attachment; {file_expr}"
diff --git a/requirements.txt b/requirements.txt
index f2908b35d..617475d6d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -39,6 +39,7 @@ aiosmtplib
 aioredis==2.0.1
 
 # PDF credentials
+urllib
 reportlab
 
 # DMARC