diff --git a/app/scodoc/sco_archives.py b/app/scodoc/sco_archives.py
index 71acd8159e..e4c86578b7 100644
--- a/app/scodoc/sco_archives.py
+++ b/app/scodoc/sco_archives.py
@@ -28,7 +28,7 @@
 """ScoDoc : gestion des archives des PV et bulletins, et des dossiers etudiants (admission)
 
 
- Archives are plain files, stored in 
+ Archives are plain files, stored in
     <SCODOC_VAR_DIR>/archives/<dept_id>
  (where <SCODOC_VAR_DIR> is usually /opt/scodoc-data, and <dept_id> a departement id (int))
 
@@ -42,7 +42,7 @@
 
  Les maquettes Apogée pour l'export des notes sont dans
     <archivedir>/apo_csv/<dept_id>/<annee_scolaire>-<sem_id>/<YYYY-MM-DD-HH-MM-SS>/<code_etape>.csv
-    
+
  Un répertoire d'archive contient des fichiers quelconques, et un fichier texte nommé _description.txt
  qui est une description (humaine, format libre) de l'archive.
 
@@ -105,13 +105,13 @@ class BaseArchiver(object):
             try:
                 scu.GSL.acquire()
                 if not os.path.isdir(path):
-                    log("creating directory %s" % path)
+                    log(f"creating directory {path}")
                     os.mkdir(path)
             finally:
                 scu.GSL.release()
                 self.initialized = True
 
-    def get_obj_dir(self, oid):
+    def get_obj_dir(self, oid: int):
         """
         :return: path to directory of archives for this object (eg formsemestre_id or etudid).
         If directory does not yet exist, create it.
@@ -142,7 +142,7 @@ class BaseArchiver(object):
         dirs = glob.glob(base + "*")
         return [os.path.split(x)[1] for x in dirs]
 
-    def list_obj_archives(self, oid):
+    def list_obj_archives(self, oid: int):
         """Returns
         :return: list of archive identifiers for this object (paths to non empty dirs)
         """
@@ -157,7 +157,7 @@ class BaseArchiver(object):
         dirs.sort()
         return dirs
 
-    def delete_archive(self, archive_id):
+    def delete_archive(self, archive_id: str):
         """Delete (forever) this archive"""
         self.initialize()
         try:
@@ -166,7 +166,7 @@ class BaseArchiver(object):
         finally:
             scu.GSL.release()
 
-    def get_archive_date(self, archive_id):
+    def get_archive_date(self, archive_id: str):
         """Returns date (as a DateTime object) of an archive"""
         return datetime.datetime(
             *[int(x) for x in os.path.split(archive_id)[1].split("-")]
@@ -183,17 +183,17 @@ class BaseArchiver(object):
         files.sort()
         return [f for f in files if f and f[0] != "_"]
 
-    def get_archive_name(self, archive_id):
+    def get_archive_name(self, archive_id: str):
         """name identifying archive, to be used in web URLs"""
         return os.path.split(archive_id)[1]
 
-    def is_valid_archive_name(self, archive_name):
+    def is_valid_archive_name(self, archive_name: str):
         """check if name is valid."""
         return re.match(
             "^[0-9]{4}-[0-9]{2}-[0-9]{2}-[0-9]{2}-[0-9]{2}-[0-9]{2}$", archive_name
         )
 
-    def get_id_from_name(self, oid, archive_name):
+    def get_id_from_name(self, oid, archive_name: str):
         """returns archive id (check that name is valid)"""
         self.initialize()
         if not self.is_valid_archive_name(archive_name):
@@ -206,7 +206,7 @@ class BaseArchiver(object):
             raise ScoValueError(f"Archive {archive_name} introuvable")
         return archive_id
 
-    def get_archive_description(self, archive_id):
+    def get_archive_description(self, archive_id: str) -> str:
         """Return description of archive"""
         self.initialize()
         filename = os.path.join(archive_id, "_description.txt")
@@ -247,7 +247,7 @@ class BaseArchiver(object):
             data = data.encode(scu.SCO_ENCODING)
         self.initialize()
         filename = scu.sanitize_filename(filename)
-        log("storing %s (%d bytes) in %s" % (filename, len(data), archive_id))
+        log(f"storing {filename} ({len(data)} bytes) in {archive_id}")
         try:
             scu.GSL.acquire()
             fname = os.path.join(archive_id, filename)
@@ -261,16 +261,18 @@ class BaseArchiver(object):
         """Retreive data"""
         self.initialize()
         if not scu.is_valid_filename(filename):
-            log('Archiver.get: invalid filename "%s"' % filename)
+            log(f"""Archiver.get: invalid filename '{filename}'""")
             raise ScoValueError("archive introuvable (déjà supprimée ?)")
         fname = os.path.join(archive_id, filename)
-        log("reading archive file %s" % fname)
+        log(f"reading archive file {fname}")
         with open(fname, "rb") as f:
             data = f.read()
         return data
 
     def get_archived_file(self, oid, archive_name, filename):
-        """Recupere donnees du fichier indiqué et envoie au client"""
+        """Recupère les donnees du fichier indiqué et envoie au client.
+        Returns: Response
+        """
         archive_id = self.get_id_from_name(oid, archive_name)
         data = self.get(archive_id, filename)
         mime = mimetypes.guess_type(filename)[0]
diff --git a/sco_version.py b/sco_version.py
index 98f0f59b52..91866c9f22 100644
--- a/sco_version.py
+++ b/sco_version.py
@@ -1,7 +1,7 @@
 # -*- mode: python -*-
 # -*- coding: utf-8 -*-
 
-SCOVERSION = "9.4.20"
+SCOVERSION = "9.4.21"
 
 SCONAME = "ScoDoc"