diff --git a/Web/app.py b/Web/app.py
index d476543..49a0cdd 100755
--- a/Web/app.py
+++ b/Web/app.py
@@ -228,96 +228,6 @@ def rollover_student_card_classes(dry_run=False, *, max_class=None, graduate_lab
             client.close()
 
 
-@app.route('/api/library_return_by_code', methods=['POST'])
-def api_library_return_by_code():
-    """
-    Return a library item by scanning its code only (no student card required).
-    This marks active ausleihungen for the item as completed and updates item status.
-    """
-    if 'username' not in session:
-        return jsonify({'ok': False, 'message': 'Nicht angemeldet.'}), 401
-    if not cfg.MODULES.is_enabled('library'):
-        return jsonify({'ok': False, 'message': 'Bibliotheks-Modul ist deaktiviert.'}), 403
-
-    payload = request.get_json(silent=True) or {}
-    item_code_raw = str(payload.get('item_code') or payload.get('code') or '').strip()
-    if not item_code_raw:
-        return jsonify({'ok': False, 'message': 'Mediencode fehlt.'}), 400
-
-    normalized_isbn = normalize_and_validate_isbn(item_code_raw)
-    normalized_code = item_code_raw.upper()
-
-    client = None
-    try:
-        client = MongoClient(MONGODB_HOST, MONGODB_PORT)
-        db = client[MONGODB_DB]
-        items_col = db['items']
-        ausleihungen_col = db['ausleihungen']
-
-        query_or = [
-            {'Code_4': item_code_raw},
-            {'Code_4': normalized_code},
-        ]
-        if normalized_isbn:
-            query_or.append({'ISBN': normalized_isbn})
-
-        item_doc = items_col.find_one({
-            'ItemType': {'$in': LIBRARY_ITEM_TYPES},
-            '$or': query_or
-        })
-
-        if not item_doc:
-            return jsonify({'ok': False, 'message': 'Kein Bibliotheksmedium für diesen Code gefunden.'}), 404
-
-        item_id = str(item_doc['_id'])
-        now = datetime.datetime.now(ZoneInfo("Europe/Berlin"))
-
-        # If item already available -> nothing to return
-        if item_doc.get('Verfuegbar', True):
-            return jsonify({'ok': False, 'message': 'Dieses Medium ist nicht als ausgeliehen markiert.'}), 409
-
-        # Mark active ausleihungen as completed
-        update_result = ausleihungen_col.update_many(
-            {'Item': item_id, 'Status': 'active'},
-            {'$set': {
-                'Status': 'completed',
-                'End': now,
-                'LastUpdated': now
-            }}
-        )
-
-        # Update item status to available
-        borrower_name = str(item_doc.get('User') or '').strip() or ''
-        it.update_item_status(item_id, True, borrower_name)
-
-        _append_audit_event_standalone(
-            event_type='ausleihung_returned_by_code',
-            payload={
-                'channel': 'library_return_code',
-                'item_id': item_id,
-                'item_name': item_doc.get('Name', ''),
-                'completed_records': update_result.modified_count,
-                'performed_by': session.get('username')
-            }
-        )
-
-        return jsonify({
-            'ok': True,
-            'action': 'returned',
-            'item_id': item_id,
-            'item_name': item_doc.get('Name', ''),
-            'completed_records': update_result.modified_count,
-            'message': f"{item_doc.get('Name', 'Medium')} wurde zurückgegeben."
-        }), 200
-    except Exception as e:
-        app.logger.error(f"Error in library return by code: {e}")
-        return jsonify({'ok': False, 'message': 'Fehler beim Verarbeiten der Rückgabe.'}), 500
-    finally:
-        if client:
-            client.close()
-
-
-
 # Admin route to trigger rollover manually
 @app.route('/admin/trigger_school_year_rollover', methods=['POST'])
 def admin_trigger_school_year_rollover():
@@ -333,33 +243,6 @@ def admin_trigger_school_year_rollover():
     return jsonify({'ok': True, 'summary': summary}), 200
 
 
-# Schedule annual rollover job using APScheduler (configurable via env)
-try:
-        if cfg.SCHEDULER_ENABLED:
-            _rollover_month = getattr(cfg, 'SCHOOL_ROLLOVER_MONTH', 9)
-            _rollover_day = getattr(cfg, 'SCHOOL_ROLLOVER_DAY', 1)
-            _rollover_hour = getattr(cfg, 'SCHOOL_ROLLOVER_HOUR', 3)
-            _rollover_minute = getattr(cfg, 'SCHOOL_ROLLOVER_MIN', 0)
-            _rollover_max_class = getattr(cfg, 'SCHOOL_ROLLOVER_MAX_CLASS', 13)
-            _rollover_grad_label = getattr(cfg, 'SCHOOL_ROLLOVER_GRADUATE_LABEL', '')
-
-            _scheduler = BackgroundScheduler()
-            # Use a cron-style yearly job on the configured month/day
-            _scheduler.add_job(
-                func=lambda: rollover_student_card_classes(dry_run=False, max_class=_rollover_max_class, graduate_label=_rollover_grad_label),
-                trigger='cron',
-                month=_rollover_month,
-                day=_rollover_day,
-                hour=_rollover_hour,
-                minute=_rollover_minute,
-                id='school_year_rollover',
-                replace_existing=True
-            )
-            _scheduler.start()
-            app.logger.info('Scheduled annual school year rollover: %s-%s %s:%s', _rollover_month, _rollover_day, _rollover_hour, _rollover_minute)
-except Exception as e:
-    app.logger.warning('Failed to schedule school year rollover: %s', e)
-
 # Thumbnail sizes
 THUMBNAIL_SIZE = cfg.THUMBNAIL_SIZE
 PREVIEW_SIZE = cfg.PREVIEW_SIZE
@@ -4291,6 +4174,93 @@ def api_library_group(series_group_id):
         app.logger.error('Error loading library group %s: %s', series_group_id, exc)
         return jsonify({'items': [], 'message': 'Gruppe konnte nicht geladen werden.'}), 500
 
+@app.route('/api/library_return_by_code', methods=['POST'])
+def api_library_return_by_code():
+    """
+    Return a library item by scanning its code only (no student card required).
+    This marks active ausleihungen for the item as completed and updates item status.
+    """
+    if 'username' not in session:
+        return jsonify({'ok': False, 'message': 'Nicht angemeldet.'}), 401
+    if not cfg.MODULES.is_enabled('library'):
+        return jsonify({'ok': False, 'message': 'Bibliotheks-Modul ist deaktiviert.'}), 403
+
+    payload = request.get_json(silent=True) or {}
+    item_code_raw = str(payload.get('item_code') or payload.get('code') or '').strip()
+    if not item_code_raw:
+        return jsonify({'ok': False, 'message': 'Mediencode fehlt.'}), 400
+
+    normalized_isbn = normalize_and_validate_isbn(item_code_raw)
+    normalized_code = item_code_raw.upper()
+
+    client = None
+    try:
+        client = MongoClient(MONGODB_HOST, MONGODB_PORT)
+        db = client[MONGODB_DB]
+        items_col = db['items']
+        ausleihungen_col = db['ausleihungen']
+
+        query_or = [
+            {'Code_4': item_code_raw},
+            {'Code_4': normalized_code},
+        ]
+        if normalized_isbn:
+            query_or.append({'ISBN': normalized_isbn})
+
+        item_doc = items_col.find_one({
+            'ItemType': {'$in': LIBRARY_ITEM_TYPES},
+            '$or': query_or
+        })
+
+        if not item_doc:
+            return jsonify({'ok': False, 'message': 'Kein Bibliotheksmedium für diesen Code gefunden.'}), 404
+
+        item_id = str(item_doc['_id'])
+        now = datetime.datetime.now(ZoneInfo("Europe/Berlin"))
+
+        # If item already available -> nothing to return
+        if item_doc.get('Verfuegbar', True):
+            return jsonify({'ok': False, 'message': 'Dieses Medium ist nicht als ausgeliehen markiert.'}), 409
+
+        # Mark active ausleihungen as completed
+        update_result = ausleihungen_col.update_many(
+            {'Item': item_id, 'Status': 'active'},
+            {'$set': {
+                'Status': 'completed',
+                'End': now,
+                'LastUpdated': now
+            }}
+        )
+
+        # Update item status to available
+        borrower_name = str(item_doc.get('User') or '').strip() or ''
+        it.update_item_status(item_id, True, borrower_name)
+
+        _append_audit_event_standalone(
+            event_type='ausleihung_returned_by_code',
+            payload={
+                'channel': 'library_return_code',
+                'item_id': item_id,
+                'item_name': item_doc.get('Name', ''),
+                'completed_records': update_result.modified_count,
+                'performed_by': session.get('username')
+            }
+        )
+
+        return jsonify({
+            'ok': True,
+            'action': 'returned',
+            'item_id': item_id,
+            'item_name': item_doc.get('Name', ''),
+            'completed_records': update_result.modified_count,
+            'message': f"{item_doc.get('Name', 'Medium')} wurde zurückgegeben."
+        }), 200
+    except Exception as e:
+        app.logger.error(f"Error in library return by code: {e}")
+        return jsonify({'ok': False, 'message': 'Fehler beim Verarbeiten der Rückgabe.'}), 500
+    finally:
+        if client:
+            client.close()
 
 @app.route('/api/library_scan_action', methods=['POST'])
 def api_library_scan_action():
@@ -4320,6 +4290,10 @@ def api_library_scan_action():
     normalized_isbn = normalize_and_validate_isbn(item_code_raw)
     normalized_code = item_code_raw.upper()
 
+    if us.student_is_blocked(student_card_id):
+        flash("User Blockiert!", "error")
+        return jsonify({'ok': False, 'message': 'User Blockiert.'}), 404
+
     client = None
     try:
         client = MongoClient(MONGODB_HOST, MONGODB_PORT)
@@ -4373,8 +4347,10 @@ def api_library_scan_action():
                     card_default = cfg.STUDENT_DEFAULT_BORROW_DAYS
                 borrow_duration_days = max(1, min(card_default, cfg.STUDENT_MAX_BORROW_DAYS))
 
+            due_date = now + datetime.timedelta(days=borrow_duration_days)
+
             it.update_item_status(item_id, False, borrower_name)
-            au.add_ausleihung(item_id, borrower_name, now)
+            au.add_ausleihung(item_id, borrower_name, now, due_date)
 
             _append_audit_event_standalone(
                 event_type='ausleihung_borrowed',
diff --git a/Web/modules/database/ausleihung.py b/Web/modules/database/ausleihung.py
index 5cbc7bd..df60065 100755
--- a/Web/modules/database/ausleihung.py
+++ b/Web/modules/database/ausleihung.py
@@ -34,6 +34,7 @@ import Web.modules.database.settings as cfg
 from Web.modules.database.settings import MongoClient
 import Web.modules.inventarsystem.data_protection as dp
 import Web.modules.database.user as us
+from zoneinfo import ZoneInfo
 
 
 def _get_client():
@@ -184,7 +185,7 @@ def create_backup_database():
 
 # === AUSLEIHUNG MANAGEMENT ===
 
-def add_ausleihung(item_id, user, start_date, end_date=None, notes="", status="active", period=None, exemplar_data=None):
+def add_ausleihung(item_id, user, start_date, end_date=None, notes="", status="active", period=None, exemplar_data=None, due_date=None):
     """
     Add a new borrowing record for an item.
     
@@ -224,6 +225,9 @@ def add_ausleihung(item_id, user, start_date, end_date=None, notes="", status="a
             
         if exemplar_data:
             ausleihung['ExemplarData'] = exemplar_data
+
+        if due_date:
+            ausleihung['DueDate'] = due_date
         
         result = ausleihungen.insert_one(ausleihung)
         ausleihung_id = result.inserted_id
diff --git a/Web/modules/database/items.py b/Web/modules/database/items.py
index 4f27630..42a13d1 100755
--- a/Web/modules/database/items.py
+++ b/Web/modules/database/items.py
@@ -26,6 +26,7 @@ import Web.modules.database.settings as cfg
 from Web.modules.database.settings import MongoClient
 import Web.modules.inventarsystem.data_protection as dp
 import logging
+from zoneinfo import ZoneInfo
 
 
 def is_library_item(item):
@@ -177,8 +178,8 @@ def add_item(name, ort, beschreibung, images=None, filter=None, filter2=None, fi
             'SeriesPosition': series_position,
             'IsGroupedSubItem': is_grouped_sub_item,
             'ParentItemId': parent_item_id,
-            'Created': datetime.datetime.now(),
-            'LastUpdated': datetime.datetime.now()
+            'Created': datetime.datetime.now(ZoneInfo("Europe/Berlin")),
+            'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
         }
         result = items.insert_one(item)
         item_id = result.inserted_id
@@ -208,8 +209,8 @@ def remove_item(id):
             {'_id': ObjectId(id), 'Deleted': {'$ne': True}},
             {'$set': {
                 'Deleted': True,
-                'DeletedAt': datetime.datetime.now(),
-                'LastUpdated': datetime.datetime.now(),
+                'DeletedAt': datetime.datetime.now(ZoneInfo("Europe/Berlin")),
+                'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin")),
                 'Verfuegbar': False,
             }}
         )
@@ -304,7 +305,7 @@ def update_item(id, name, ort, beschreibung, images, verfuegbar, filter1, filter
             'is_library': is_lib,
             'library_category': library_category,
             'Verfuegbar': bool(verfuegbar),
-            'LastUpdated': datetime.datetime.now()
+            'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
         }
 
         specific_update = shared_update.copy()
@@ -346,7 +347,7 @@ def update_item_status(id, verfuegbar, user=None):
 
         update_data = {
             'Verfuegbar': verfuegbar,
-            'LastUpdated': datetime.datetime.now()
+            'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
         }
 
         update_query = {'$set': update_data}
@@ -387,7 +388,7 @@ def update_item_exemplare_status(id, exemplare_status):
 
         update_data = {
             'ExemplareStatus': exemplare_status,
-            'LastUpdated': datetime.datetime.now()
+            'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
         }
 
         result = items.update_one(
@@ -734,7 +735,7 @@ def unstuck_item(id):
             {'$set': {
                 'Status': 'cancelled',
                 'CancelledReason': 'unstuck_reset',
-                'LastUpdated': datetime.datetime.now()
+                'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
             }}
         )
 
@@ -745,7 +746,7 @@ def unstuck_item(id):
             {
                 '$set': {
                     'Verfuegbar': True,
-                    'LastUpdated': datetime.datetime.now()
+                    'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
                 },
                 '$unset': {'User': ""}
             }
@@ -1075,7 +1076,7 @@ def update_item_next_appointment(item_id, appointment_data):
         if appointment_data is None:
             update_query = {
                 '$unset': {'NextAppointment': ""},
-                '$set': {'LastUpdated': datetime.datetime.now()}
+                '$set': {'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))}
             }
         else:
             # Create a copy so we don't mutate the original dictionary passed in
@@ -1088,7 +1089,7 @@ def update_item_next_appointment(item_id, appointment_data):
             update_query = {
                 '$set': {
                     'NextAppointment': data_to_save,
-                    'LastUpdated': datetime.datetime.now()
+                    'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
                 }
             }
 
@@ -1121,7 +1122,7 @@ def clear_item_next_appointment(item_id):
 
         result = items.update_one(
             {'_id': ObjectId(item_id)},
-            {'$unset': {'NextAppointment': ""}, '$set': {'LastUpdated': datetime.datetime.now()}}
+            {'$unset': {'NextAppointment': ""}, '$set': {'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))}}
         )
 
         client.close()
diff --git a/Web/modules/database/termine.py b/Web/modules/database/termine.py
index 145f912..cd7c543 100644
--- a/Web/modules/database/termine.py
+++ b/Web/modules/database/termine.py
@@ -23,6 +23,7 @@ from Web.modules.database.settings import MongoClient
 from bson.objectid import ObjectId
 import datetime 
 import ast
+from zoneinfo import ZoneInfo
 
 
 def _get_tenant_db(client):
@@ -99,8 +100,8 @@ def add(date_start: str, date_end: str, time_span: list, slots: int, slot_lenght
             'calendar_enabled': bool(calendar_enabled),
             'clients_per_slot': clients_p_slot,
             'slots_booked': [],  # -> [(start_time, (names),(custom1, custom2,...)), ...]the list gets there indexes as the slot 1-defined so is can be counted without an extra variable
-            'Created': datetime.datetime.now(),
-            'LastUpdated': datetime.datetime.now()
+            'Created': datetime.datetime.now(ZoneInfo("Europe/Berlin")),
+            'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
         }
         result = items.insert_one(item)
         return result.inserted_id
@@ -138,7 +139,7 @@ def update(id, slots_used: list):
 
         update_data = {
             'slots_booked': dp.encrypt_text(str(slots_used)),
-            'LastUpdated': datetime.datetime.now()
+            'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
         }
 
         result = items.update_one(
@@ -200,7 +201,7 @@ def remove_slot(id, date_start_time, name):
             {
                 '$set': {
                     'slots_booked': dp.encrypt_text(str(updated_slots)),
-                    'LastUpdated': datetime.datetime.now()
+                    'LastUpdated': datetime.datetime.now(ZoneInfo("Europe/Berlin"))
                 }
             }
         )
diff --git a/Web/modules/database/user.py b/Web/modules/database/user.py
index 2ec235a..8f8448c 100755
--- a/Web/modules/database/user.py
+++ b/Web/modules/database/user.py
@@ -740,6 +740,87 @@ def get_user_by_student_ident(student_ident):
 
     return None
 
+
+def get_user_by_student_name(student_name):
+    """Return user dict by student name by decrypting all cards and matching."""
+    if not student_name:
+        return None
+
+    # Normalisiere den Suchbegriff, den wir finden wollen
+    normalized_target = str(student_name).strip()
+    if not normalized_target:
+        return None
+
+    client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
+    try:
+        db = _get_tenant_db(client)
+        all_student_cards = db['student_cards'].find()
+
+        for user_doc in all_student_cards:
+            encrypted_student_name = user_doc.get('SchülerName')
+
+            if encrypted_student_name:
+                try:
+                    decrypted_ident = dp.decrypt_text(encrypted_student_name)
+
+                    if decrypted_ident and str(decrypted_ident).strip() == normalized_target:
+                        return user_doc
+
+                except Exception as e:
+                    logger.error(f"Entschlüsselungsfehler bei ID {user_doc.get('_id')}: {e}")
+                    continue
+
+    except Exception as exc:
+        logger.error(f"Datenbankfehler in get_user_by_student_name: {exc}")
+    finally:
+        client.close()
+
+    return None
+
+def student_is_blocked(student_id):
+    """
+    Überprüft, ob ein Schüler (Nutzer) im System gesperrt ist (z. B. aufgrund von überfälligen Ausleihen).
+    Akzeptiert entweder den Benutzernamen oder die Schülerausweis-ID.
+
+    Rückgabewert:
+        True, wenn der Nutzer gesperrt ist.
+        False, wenn der Nutzer nicht gesperrt ist oder nicht gefunden wurde.
+    """
+    if not student_id:
+        return False
+
+    normalized_card_id = normalize_student_card_id(student_id)
+
+    client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
+    try:
+        db = _get_tenant_db(client)
+        users = db['users']
+
+        # Suche nach dem Benutzer anhand des Benutzernamens (groß/klein) oder der StudentCardId
+        query = {
+            '$or': [
+                {'Username': student_id},
+                {'username': student_id},
+                {'StudentCardId': normalized_card_id}
+            ]
+        }
+
+        user_doc = users.find_one(query)
+
+        if user_doc:
+            # Lese das Feld 'is_blocked' aus, standardmäßig False, falls es nicht existiert
+            return bool(user_doc.get('is_blocked', False))
+
+        # Wenn kein Nutzer gefunden wurde, gehen wir sicherheitshalber davon aus, dass keine Sperre vorliegt
+        return False
+
+    except Exception as e:
+        logger.error(f"Datenbankfehler in student_is_blocked: {e}")
+        # Im Fehlerfall False zurückgeben, um Systemblockaden durch Datenbankfehler zu vermeiden
+        return False
+    finally:
+        client.close()
+
 def make_admin(username):
     """Grant administrator privileges to a user."""
     client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
diff --git a/Web/push_notifications.py b/Web/push_notifications.py
index 6e3fa1e..f28d8df 100644
--- a/Web/push_notifications.py
+++ b/Web/push_notifications.py
@@ -10,6 +10,7 @@ from bson import ObjectId
 import requests
 import hashlib
 import logging
+from zoneinfo import ZoneInfo
 
 import Web.modules.database.settings as cfg
 from Web.modules.database.settings import MongoClient
@@ -153,7 +154,7 @@ def save_push_subscription(username, subscription_obj):
             subs_col.update_one(
                 {'_id': existing['_id']},
                 {'$set': {
-                    'LastUsed': datetime.datetime.now(),
+                    'LastUsed': datetime.datetime.now(ZoneInfo("Europe/Berlin")),
                     'IsActive': True
                 }}
             )
@@ -172,8 +173,8 @@ def save_push_subscription(username, subscription_obj):
             'Keys': encrypt_text(keys_str),
             'SubscriptionHash': sub_hash,
             'IsActive': True,
-            'CreatedAt': datetime.datetime.now(),
-            'LastUsed': datetime.datetime.now(),
+            'CreatedAt': datetime.datetime.now(ZoneInfo("Europe/Berlin")),
+            'LastUsed': datetime.datetime.now(ZoneInfo("Europe/Berlin")),
             'UserAgent': subscription_obj.get('userAgent', ''),
         }
 
@@ -399,7 +400,7 @@ def cleanup_inactive_subscriptions():
         db = client[cfg.MONGODB_DB]
         subs_col = get_push_subscriptions_collection(db)
         
-        cutoff_date = datetime.datetime.now() - datetime.timedelta(days=30)
+        cutoff_date = datetime.datetime.now(ZoneInfo("Europe/Berlin")) - datetime.timedelta(days=30)
         
         result = subs_col.delete_many({
             'IsActive': False,
diff --git a/Web/tenant.py b/Web/tenant.py
index 066828e..1bf4372 100644
--- a/Web/tenant.py
+++ b/Web/tenant.py
@@ -17,6 +17,7 @@ import re
 import ipaddress
 import Web.modules.database.settings as cfg
 from Web.modules.database.settings import MongoClient
+from zoneinfo import ZoneInfo
 
 logger = logging.getLogger(__name__)
 
@@ -325,7 +326,7 @@ def get_tenant_trial_status(tenant_id=None, now=None):
     "expires_after_days", "ttl_days", or "days".
     """
     trial_config = get_tenant_trial_config(tenant_id)
-    now = now or datetime.datetime.now()
+    now = now or datetime.datetime.now(ZoneInfo("Europe/Berlin"))
 
     enabled = bool(trial_config.get('enabled') or trial_config.get('active'))
     if not enabled:
@@ -447,7 +448,7 @@ def delete_tenant(tenant_id, *, drop_database=True, remove_from_config=True):
 
 def purge_expired_trial_tenants(now=None):
     """Delete expired trial tenants that opted into auto-delete."""
-    now = now or datetime.datetime.now()
+    now = now or datetime.datetime.now(ZoneInfo("Europe/Berlin"))
     purged_tenants = []
 
     for tenant_id in list(TENANT_REGISTRY.keys()):