diff --git a/app/scodoc/sco_debouche.py b/app/scodoc/sco_debouche.py
index 52e17e167..259e8372c 100644
--- a/app/scodoc/sco_debouche.py
+++ b/app/scodoc/sco_debouche.py
@@ -149,13 +149,15 @@ def table_debouche_etudids(etudids, keep_numeric=True):
         if itemsuivis:
             if keep_numeric:  # pour excel:
                 row["debouche"] = "\n".join(
-                    f"""{it.item_date.strftime(scu.DATE_FMT)}: {it.situation or ""}"""
+                    f"""{it.item_date.strftime(scu.DATE_FMT) if it.item_date else ""
+                    } : {it.situation or ""}"""
                     for it in itemsuivis
                 )
             else:
                 row["debouche"] = "<br>".join(
                     [
-                        f"""{it.item_date.strftime(scu.DATE_FMT)} : {it.situation or ""}
+                        f"""{it.item_date.strftime(scu.DATE_FMT) if it.item_date else ""
+                        } : {it.situation or ""}
                         <i>{', '.join( tag.title for tag in it.tags)}</i>
                         """
                         for it in itemsuivis
diff --git a/app/views/assiduites.py b/app/views/assiduites.py
index eb9e59694..46c47663e 100644
--- a/app/views/assiduites.py
+++ b/app/views/assiduites.py
@@ -974,7 +974,14 @@ def calendrier_assi_etud():
     mode_demi: bool = scu.to_bool(request.args.get("mode_demi", "t"))
     show_pres: bool = scu.to_bool(request.args.get("show_pres", "f"))
     show_reta: bool = scu.to_bool(request.args.get("show_reta", "f"))
-    annee: int = int(request.args.get("annee", scu.annee_scolaire()))
+    annee_str = request.args.get("annee", "")
+    if not annee_str:
+        annee = scu.annee_scolaire()
+    else:
+        try:
+            annee = int(annee_str)
+        except ValueError as exc:
+            raise ScoValueError("année invalide") from exc
 
     # Récupération des années d'étude de l'étudiant
     annees: list[int] = []
diff --git a/sco_version.py b/sco_version.py
index cf12c24ab..9b3ad1536 100644
--- a/sco_version.py
+++ b/sco_version.py
@@ -1,7 +1,7 @@
 # -*- mode: python -*-
 # -*- coding: utf-8 -*-
 
-SCOVERSION = "9.7.23"
+SCOVERSION = "9.7.24"
 
 SCONAME = "ScoDoc"