diff --git a/.github/workflows/build_docker_image.yml b/.github/workflows/build_docker_image.yml
index 053f800..b93e49b 100644
--- a/.github/workflows/build_docker_image.yml
+++ b/.github/workflows/build_docker_image.yml
@@ -15,7 +15,7 @@ jobs:
 
     services:
       mariadb:
-        image: mariadb:10.2
+        image: mariadb:10.4
         env:
           MARIADB_USER: amelie_test
           MARIADB_PASSWORD: amelie_test
diff --git a/amelie/activities/migrations/0011_alter_activity_components.py b/amelie/activities/migrations/0011_alter_activity_components.py
new file mode 100644
index 0000000..e4d8114
--- /dev/null
+++ b/amelie/activities/migrations/0011_alter_activity_components.py
@@ -0,0 +1,18 @@
+# Generated by Django 4.2.11 on 2024-04-14 16:38
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('activities', '0010_auto_20221031_2218'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='activity',
+            name='components',
+            field=models.ManyToManyField(blank=True, to='activities.activity'),
+        ),
+    ]
diff --git a/amelie/api/common.py b/amelie/api/common.py
index b8f3f08..4448da1 100644
--- a/amelie/api/common.py
+++ b/amelie/api/common.py
@@ -32,4 +32,4 @@ def strip_markdown(markdowntext):
     :return: Text without markdown formatting.
     :rtype: unicode
     """
-    return ''.join(BeautifulSoup(markdown(markdowntext), "html.parser").findAll(text=True))
+    return ''.join(BeautifulSoup(markdown(markdowntext), "html.parser").findAll(string=True))
diff --git a/amelie/calendar/participation_urls.py b/amelie/calendar/participation_urls.py
index 870bb6e..b9d372b 100644
--- a/amelie/calendar/participation_urls.py
+++ b/amelie/calendar/participation_urls.py
@@ -1,9 +1,9 @@
-from django.conf.urls import url
+from django.urls import re_path
 
 from amelie.calendar import views
 
 app_name = 'calendar'
 
 urlpatterns = [
-    url(r'^(?P<pk>\d+)/pay/', views.PayParticipationView.as_view(), name='pay_participation'),
+    re_path(r'^(?P<pk>\d+)/pay/', views.PayParticipationView.as_view(), name='pay_participation'),
 ]
diff --git a/amelie/calendar/views.py b/amelie/calendar/views.py
index 6b08de2..c48139b 100644
--- a/amelie/calendar/views.py
+++ b/amelie/calendar/views.py
@@ -1,7 +1,7 @@
 from django.contrib import messages
 from django.shortcuts import get_object_or_404, redirect
 from django.utils import timezone
-from django.utils.translation import ugettext_lazy as _l
+from django.utils.translation import gettext_lazy as _l
 from django.views.generic import TemplateView
 
 from amelie.calendar.models import Participation
diff --git a/amelie/claudia/claudia_views.py b/amelie/claudia/claudia_views.py
index 65f476c..5798633 100644
--- a/amelie/claudia/claudia_views.py
+++ b/amelie/claudia/claudia_views.py
@@ -6,7 +6,7 @@
 from django.views.generic import ListView, DetailView, View, TemplateView
 from django.views.generic.edit import UpdateView, CreateView, DeleteView, FormView
 from django.views.generic.detail import SingleObjectMixin
-from django.utils.translation import ugettext_lazy as _l
+from django.utils.translation import gettext_lazy as _l
 
 from amelie.settings import SYSADMINS_ABBR
 from amelie.tools.mixins import RequireCommitteeMixin, RequireStrictCommitteeMixin
diff --git a/amelie/education/views.py b/amelie/education/views.py
index c40c446..72c5689 100644
--- a/amelie/education/views.py
+++ b/amelie/education/views.py
@@ -5,7 +5,7 @@
 from django.shortcuts import render, get_object_or_404, redirect
 from django.utils import timezone
 from django.utils.encoding import force_str
-from django.utils.http import is_safe_url
+from django.utils.http import url_has_allowed_host_and_scheme
 from django.views.decorators.http import require_http_methods
 from django.views.generic import TemplateView
 
@@ -384,7 +384,7 @@ def course_new(request):
         if form.is_valid():
             course_obj = form.save()
             course_obj.save()
-            if next and is_safe_url(next, [request.get_host()]):
+            if next and url_has_allowed_host_and_scheme(next, [request.get_host()]):
                 return redirect(next)
             return redirect("education:complaint_new")
 
@@ -401,7 +401,7 @@ def module_new(request):
         if form.is_valid():
             module_obj = form.save()
             module_obj.save()
-            if next and is_safe_url(next, [request.get_host()]):
+            if next and url_has_allowed_host_and_scheme(next, [request.get_host()]):
                 return redirect(next)
             return redirect("education:complaint_new")
 
diff --git a/amelie/members/forms.py b/amelie/members/forms.py
index 6293120..5356ccc 100644
--- a/amelie/members/forms.py
+++ b/amelie/members/forms.py
@@ -46,7 +46,7 @@ def save(self, *args, **kwargs):
                 if field == "preferences":
                     old = [preference.name for preference in getattr(old_person, field).all()]
                     new = [preference.name for preference in self.cleaned_data[field].all()] + [preference.name for preference in self.instance.preferences.filter(adjustable=False)]
-                    
+
                     added = list(set(new)-set(old))
                     removed = list(set(old)-set(new))
 
diff --git a/amelie/members/urls.py b/amelie/members/urls.py
index 40a57fe..4231afd 100644
--- a/amelie/members/urls.py
+++ b/amelie/members/urls.py
@@ -1,5 +1,4 @@
-from django.conf.urls import include
-from django.urls import path
+from django.urls import path, include
 
 
 app_name = 'members'
diff --git a/amelie/oauth/forms.py b/amelie/oauth/forms.py
index 0375ca8..f750efa 100644
--- a/amelie/oauth/forms.py
+++ b/amelie/oauth/forms.py
@@ -1,6 +1,6 @@
 from django import forms
 from django.forms import widgets
-from django.utils.translation import ugettext_lazy as _l
+from django.utils.translation import gettext_lazy as _l
 
 
 class OAuth2RequestForm(forms.Form):
diff --git a/amelie/settings/environ.py b/amelie/settings/environ.py
index d44753b..6c99512 100644
--- a/amelie/settings/environ.py
+++ b/amelie/settings/environ.py
@@ -49,6 +49,19 @@ def get_random_secret_key_no_dollar():
 PYDEV_DEBUGGER        = False
 PYDEV_DEBUGGER_IP     = None
 
+# Load the debug toolbar -- does not need to be changed in principle
+if DEBUG_TOOLBAR:
+    def custom_show_toolbar(request):
+        return True
+
+    # Order is important
+    INSTALLED_APPS = INSTALLED_APPS + ('debug_toolbar',)
+    MIDDLEWARE = ['debug_toolbar.middleware.DebugToolbarMiddleware'] + MIDDLEWARE
+
+    DEBUG_TOOLBAR_CONFIG = {
+        'SHOW_TOOLBAR_CALLBACK': '%s.%s' % (__name__, custom_show_toolbar.__name__),
+    }
+
 # Do not redirect to HTTPS, because the nginx proxy container only listens on HTTP
 SECURE_SSL_REDIRECT   = False
 
diff --git a/amelie/settings/generic.py b/amelie/settings/generic.py
index 0bc9944..eb365e6 100644
--- a/amelie/settings/generic.py
+++ b/amelie/settings/generic.py
@@ -208,6 +208,8 @@
     'mozilla_django_oidc.middleware.SessionRefresh',  # Verify OIDC session tokens
 ]
 
+INTERNAL_IPS = ['127.0.0.1', 'localhost', '172.17.0.1']
+
 # Authentication backends used by the application
 AUTHENTICATION_BACKENDS = [
     'amelie.tools.auth.IAOIDCAuthenticationBackend',  # Logins via OIDC / auth.ia
@@ -302,7 +304,7 @@
     'ckeditor_uploader',
 
     # SSL Runserver
-    'sslserver',
+    # 'sslserver',
 
     # Django-celery helper for celery results
     'django_celery_results',
diff --git a/amelie/tools/cache.py b/amelie/tools/cache.py
index f2dcef9..6237fd4 100644
--- a/amelie/tools/cache.py
+++ b/amelie/tools/cache.py
@@ -1,4 +1,4 @@
-from threading import currentThread
+from threading import current_thread
 
 from django.core.cache.backends.locmem import LocMemCache
 from django.utils.deprecation import MiddlewareMixin
@@ -12,13 +12,13 @@ def get_request_cache():
         temp = RequestCacheMiddleware()
         temp.process_request(None)
 
-    return _request_cache[currentThread()]
+    return _request_cache[current_thread()]
 
 
 # LocMemCache is a threadsafe local memory cache
 class RequestCache(LocMemCache):
     def __init__(self):
-        name = 'locmemcache@%i' % hash(currentThread())
+        name = 'locmemcache@%i' % hash(current_thread())
         params = dict()
         super(RequestCache, self).__init__(name, params)
 
@@ -31,7 +31,7 @@ def __init__(self, *args, **kwargs):
 
     # noinspection PyMethodMayBeStatic,PyUnusedLocal
     def process_request(self, request):
-        cache = _request_cache.get(currentThread()) or RequestCache()
-        _request_cache[currentThread()] = cache
+        cache = _request_cache.get(current_thread()) or RequestCache()
+        _request_cache[current_thread()] = cache
 
         cache.clear()
diff --git a/amelie/tools/middleware.py b/amelie/tools/middleware.py
index 3da3690..80085e4 100644
--- a/amelie/tools/middleware.py
+++ b/amelie/tools/middleware.py
@@ -36,6 +36,5 @@ def process_request(self, request):
             request.is_board = request.user.is_superuser or request.person.is_board()
             request.is_education_committee = request.is_board or request.person.is_education_committee()
 
-            if not request.session.get(translation.LANGUAGE_SESSION_KEY, False):
-                preferred_language = request.person.preferred_language
-                translation.activate(preferred_language)
+            preferred_language = request.person.preferred_language
+            translation.activate(preferred_language)
diff --git a/amelie/urls.py b/amelie/urls.py
index 708110a..eb3ba96 100644
--- a/amelie/urls.py
+++ b/amelie/urls.py
@@ -1,9 +1,8 @@
 import oauth2_provider.views
 
 from django.conf import settings
-from django.conf.urls import include
 from django.contrib import admin
-from django.urls import reverse_lazy, path, re_path
+from django.urls import reverse_lazy, path, re_path, include
 from django.contrib.auth.views import LogoutView
 from django.views.generic.base import RedirectView
 from django.views.static import serve
@@ -20,7 +19,6 @@
     path('admin/', admin.site.urls),
     path('legacy_login/', views.login, name='legacy_login'),
     path('legacy_logout/', LogoutView.as_view(), name='legacy_logout'),
-    path('i18n/', include('django.conf.urls.i18n')),
     path('profile/', views.profile_overview, name='profile_overview'),
     path('profile/edit/', views.profile_edit, name='profile_edit'),
     path('profile/<str:action>/<str:user_id>/<str:arg>/', views.profile_actions, name='profile_actions'),
@@ -137,11 +135,9 @@
 
 
 if settings.DEBUG_TOOLBAR:
-    import debug_toolbar
+    from debug_toolbar.toolbar import debug_toolbar_urls
     # Django debug toolbar
-    urlpatterns += [
-        path('__debugtoolbar__/', include(debug_toolbar.urls), name='django_debug_toolbar')
-    ]
+    urlpatterns += debug_toolbar_urls()
 
 # Redirect for 500 errors
 handler500 = views.server_error
diff --git a/locale/nl/LC_MESSAGES/django.mo b/locale/nl/LC_MESSAGES/django.mo
index 6045ae5..d374192 100644
Binary files a/locale/nl/LC_MESSAGES/django.mo and b/locale/nl/LC_MESSAGES/django.mo differ
diff --git a/requirements.txt b/requirements.txt
index 712b2cc..3d31e9b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,6 @@
-Django>=3.2.16,<3.3
-
+Django>=4.2.11,<4.3
 importlib-metadata>=1.4.0,<5.0  # importlib-metadata 5+ causes Celery bug: https://github.com/celery/celery/issues/7783
-celery>=5.2.7,<5.3
+celery>=5.3.5,<5.4
 flower==1.2.0
 django-celery-results>=2.4,<2.5
 
@@ -9,7 +8,6 @@ django-allow-cidr>=0.5.0,<0.6
 django-compressor>=4.1,<4.2
 django-localflavor>=3.1,<3.2
 django-extensions>=3.2.1,<3.3
-django-iban>=0.3.1,<0.4
 django-formtools>=2.4,<2.5
 django-auditlog>=2.2.0,<2.3
 django-oauth-toolkit>=1.7.1,<1.8  # 2.x has breaking changes.
@@ -21,22 +19,23 @@ django-environ
 django-modern-rpc>=1.0.1,<1.1
 
 # WYSIWYG Editor for Django
-django-ckeditor>=6.3.2,<6.4  # 6.4+ requires Python3.8+ and Django 3.2+
+django-ckeditor>=6.3.2
 
 # FCM (Firebase Cloud Messaging)
-fcm-django>=0.3.11,<0.4  # 1.x has breaking changes (old firebase api removed)
-
-# Custom forks or specific commits of django packages
-git+https://github.com/Inter-Actief/django-sslserver@204586ce686212a4c2848c12f88f7279802b5dcc
+fcm-django>=0.3.11,<1  # 1.x has breaking changes (old firebase api removed) # TODO: Breaking
 
-# Other random dependencies, to be documented, see issue #556 ...
+# Used for stripping Markdown notations and indexing the IA Summary website.
 beautifulsoup4>=4.11.1,<4.12
+
+# Sanitizing Markdown strings in amelie template tags
 bleach>=5.0.1,<5.1
+
+# Other random dependencies, to be documented, see issue #556 ...
 httplib2>=0.20.4,<0.21
 icalendar>=4.1.0,<4.2
 Markdown>=3.3.7,<3.4  # 3.4+ has breaking changes in changelog that have not been checked.
 markdown2>=2.4.5,<2.5
-mysqlclient>=2.1.1,<2.2
+mysqlclient
 # Pillow requires libjpeg-dev zlib1g-dev (on Debian)
 Pillow>=9.2.0,<9.3
 python-gitlab>=3.10,<3.11.0
@@ -44,13 +43,13 @@ python-dateutil>=2.8.2,<2.9
 # python-ldap requires libldap-dev libsasl2-dev (on Debian) to build
 python-ldap>=3.4.3,<3.5
 raven>=6.10.0,<6.11
-reportlab>=3.6.11,<3.7
-requests>=2.28.1,<2.29
+reportlab>=3.6.11
+requests>=2.28.1,<2.32
 twython>=3.9.1,<3.10
-html2text>=2020.1.16,<2021.2
+html2text>=2020.1.16,<2024.2.26
 
 # Daphne - to run the website in ASGI mode on a proper webserver
-daphne>=3.0,<3.1
+daphne>=3.0,<4.2
 # UWSGI - to run the website in WSGI mode on a proper webserver
 uwsgi>=2.0,<2.1
 
@@ -62,20 +61,17 @@ google-api-python-client>=2.63.0,<3
 oauth2client>=4.1.3,<4.2
 pyOpenSSL>=22.1.0,<23.3.0  # PKCS12 deprecation in 23.3.0, need to migrate gsuite plugin to google-auth-oauthlib. See https://googleapis.github.io/google-api-python-client/docs/oauth.html
 
-# Mastodon API wrapper
-Mastodon.py>=1.5.1,<1.6
-
 # Development
-django-debug-toolbar>=3.7,<3.8
+django-debug-toolbar>=3.7,<4.5
 django-rosetta>=0.9.8,<0.10
 docutils>=0.19,<0.20
-pyinotify>=0.9.6,<0.10
-model_bakery>=1.7.0,<1.8
-django-silk>=5.0.1,<5.1
+pyinotify
+model_bakery>=1.7.0,<1.19
+django-silk>=5.0.1,<5.2
 
 # SAML IdP (requires xmlsec1 (on Debian))
-pysaml2>=7.2.1,<7.3
-djangosaml2idp>=0.7.2,<0.8
+pysaml2>=7.2.1,<7.5
+djangosaml2idp>=0.7.2,<0.8 #TODO: Officially only supports Django up-and-till 3.0 (not updated for the last 3 years)
 
 # Single Sign On - OIDC Client
 mozilla-django-oidc