diff --git a/castellum/appointments/mixins.py b/castellum/appointments/mixins.py
index 1145ae937d959bb6b25175895e3c3c819cd7f5ff..54bee5d13d8500d7768cdfb2d494a9e56e64fab1 100644
--- a/castellum/appointments/mixins.py
+++ b/castellum/appointments/mixins.py
@@ -33,7 +33,7 @@ from castellum.castellum_auth.mixins import PermissionRequiredMixin
 from castellum.recruitment.mixins import ParticipationMixin
 from castellum.recruitment.models import Participation
 from castellum.utils import add_working_days
-from castellum.utils.feeds import BaseICalFeed
+from castellum.utils.feeds import BaseCalendarFeed
 from castellum.utils.mail import MailContext
 
 from .forms import AppointmentsForm
@@ -137,12 +137,12 @@ class BaseCalendarView(DetailView):
             return super().get(request, *args, **kwargs)
 
 
-class BaseAppointmentFeed(BaseICalFeed):
-    def items(self, obj):
+class BaseAppointmentFeed(BaseCalendarFeed):
+    def items(self):
         return Appointment.objects.filter(participation__status=Participation.INVITED)
 
-    def item_start_datetime(self, item):
+    def item_start(self, item):
         return item.start
 
-    def item_end_datetime(self, item):
+    def item_end(self, item):
         return item.end
diff --git a/castellum/castellum_auth/mixins.py b/castellum/castellum_auth/mixins.py
index 13ef0ec86712b265670b5802cb8afecb78945d88..74c955f3d0db031a2123e1d8c4fdaaf4186d8b25 100644
--- a/castellum/castellum_auth/mixins.py
+++ b/castellum/castellum_auth/mixins.py
@@ -39,37 +39,25 @@ class PermissionRequiredMixin(auth_mixins.PermissionRequiredMixin):
 
 
 class APIAuthMixin(StrongholdPublicMixin):
-    """Similar to PermissionRequiredMixin.
+    """Authenticate with token header instead of login.
 
-    Differences:
-    -   Does not redirect to login on error
-    -   Gets request.user from the HTTP_AUTHORIZATION header
+    This should be the first mixin so that authentication is checked
+    before anything else.
     """
-    permission_required = None
 
-    def handle_no_permission(self):
-        raise PermissionDenied
+    raise_exception = True
 
-    def get_permission_required(self):
-        return self.permission_required
-
-    def get_permission_object(self):
-        return None
-
-    def has_permission(self):
-        perms = self.get_permission_required()
-        permission_object = self.get_permission_object()
-        return self.request.user.has_perms(perms, obj=permission_object)
-
-    def authenticate(self):
+    def get_token(self):
         auth = self.request.headers.get('Authorization', '').split()
         if len(auth) != 2 or auth[0].lower() != 'token':
-            self.handle_no_permission()
+            raise PermissionDenied
+        return auth[1]
 
+    def authenticate(self):
         try:
-            user = User.objects.get(token=auth[1])
+            user = User.objects.get(token=self.get_token())
         except User.DoesNotExist:
-            self.handle_no_permission()
+            raise PermissionDenied
 
         if not user.expiration_date:
             raise PermissionDenied('Account is not activated.')
@@ -80,6 +68,11 @@ class APIAuthMixin(StrongholdPublicMixin):
 
     def dispatch(self, request, *args, **kwargs):
         self.request.user = self.authenticate()
-        if not self.has_permission():
-            return self.handle_no_permission()
         return super().dispatch(request, *args, **kwargs)
+
+
+class ParamAuthMixin(APIAuthMixin):
+    def get_token(self):
+        if 'token' not in self.request.GET:
+            raise PermissionDenied
+        return self.request.GET['token']
diff --git a/castellum/execution/api.py b/castellum/execution/api.py
index 617fda9570719a3658bd9dc6b19daf1913961960..f7983b3e057a7086bb8a8dd739b249b164f086e2 100644
--- a/castellum/execution/api.py
+++ b/castellum/execution/api.py
@@ -30,6 +30,7 @@ from django.shortcuts import get_object_or_404
 from django.views.generic import View
 
 from castellum.castellum_auth.mixins import APIAuthMixin
+from castellum.castellum_auth.mixins import PermissionRequiredMixin
 from castellum.pseudonyms.helpers import get_pseudonym
 from castellum.pseudonyms.helpers import get_subject
 from castellum.pseudonyms.models import Domain
@@ -42,7 +43,7 @@ from castellum.subjects.models import Subject
 monitoring_logger = logging.getLogger('monitoring.execution')
 
 
-class BaseAPIView(StudyMixin, APIAuthMixin, View):
+class BaseAPIView(APIAuthMixin, StudyMixin, PermissionRequiredMixin, View):
     permission_required = ['recruitment.conduct_study']
     study_status = [Study.EXECUTION]
 
diff --git a/castellum/execution/feeds.py b/castellum/execution/feeds.py
index ce34798188981f8e3cf10e814bc3008bd19cf786..fbf34e07b4fb9148a952012c3a53031e6c491941 100644
--- a/castellum/execution/feeds.py
+++ b/castellum/execution/feeds.py
@@ -19,12 +19,13 @@
 # License along with Castellum. If not, see
 # <http://www.gnu.org/licenses/>.
 
-from django.core.exceptions import PermissionDenied
-from django.shortcuts import get_object_or_404
 from django.urls import reverse
 from django.utils.translation import gettext_lazy as _
 
 from castellum.appointments.mixins import BaseAppointmentFeed
+from castellum.castellum_auth.mixins import ParamAuthMixin
+from castellum.castellum_auth.mixins import PermissionRequiredMixin
+from castellum.studies.mixins import StudyMixin
 from castellum.studies.models import Study
 
 
@@ -41,34 +42,26 @@ class BaseExecutionAppointmentFeed(BaseAppointmentFeed):
             item.session.study.pk, item.participation.pk
         ])
 
-    def item_description(self, item):
-        return self.request.build_absolute_uri(self.item_link(item))
 
+class AppointmentFeedForStudy(
+    ParamAuthMixin, StudyMixin, PermissionRequiredMixin, BaseExecutionAppointmentFeed
+):
+    permission_required = 'recruitment.conduct_study'
+    study_status = [Study.EXECUTION]
 
-class AppointmentFeedForStudy(BaseExecutionAppointmentFeed):
-    def get_object(self, request, *args, **kwargs):
-        study = get_object_or_404(Study, pk=kwargs['pk'], status=Study.EXECUTION)
-        perms = ['recruitment.conduct_study', 'studies.access_study']
-        if not self.request.user.has_perms(perms, obj=study):
-            raise PermissionDenied
-        return study
-
-    def items(self, study):
-        return super().items(study)\
-            .filter(session__study=study)\
+    def items(self):
+        return super().items()\
+            .filter(session__study=self.study)\
             .select_related('participation__subject', 'session__study')
 
 
-class AppointmentFeedForUser(BaseExecutionAppointmentFeed):
-    def get_object(self, request, *args, **kwargs):
-        return self.request.user
-
-    def items(self, user):
-        items = super().items(user)\
+class AppointmentFeedForUser(ParamAuthMixin, BaseExecutionAppointmentFeed):
+    def items(self):
+        items = super().items()\
             .filter(session__study__status=Study.EXECUTION)\
             .select_related('participation__subject', 'session__study')
 
         perms = ['recruitment.conduct_study', 'studies.access_study']
         for item in items:
-            if user.has_perms(perms, obj=item.session.study):
+            if self.request.user.has_perms(perms, obj=item.session.study):
                 yield item
diff --git a/castellum/execution/urls.py b/castellum/execution/urls.py
index 51e98ff495404765df29f3e8921cbd26f38fc92e..af1e31c6df7475006a136cceba98bed0304610c6 100644
--- a/castellum/execution/urls.py
+++ b/castellum/execution/urls.py
@@ -52,12 +52,12 @@ from .views import TagView
 
 app_name = 'execution'
 urlpatterns = [
-    path('calendar/feed/', AppointmentFeedForUser(), name='calendar-user-feed'),
+    path('calendar/feed/', AppointmentFeedForUser.as_view(), name='calendar-user-feed'),
     path('<int:study_pk>/', StudyDetailView.as_view(), name='study-detail'),
     path('<int:study_pk>/resolve/', ResolveView.as_view(), name='resolve'),
     path('<int:study_pk>/news/', NewsMailView.as_view(), name='news-mail'),
     path('<int:pk>/calendar/', CalendarView.as_view(), name='calendar'),
-    path('<int:pk>/calendar/feed/', AppointmentFeedForStudy(), name='calendar-feed'),
+    path('<int:pk>/calendar/feed/', AppointmentFeedForStudy.as_view(), name='calendar-feed'),
     path('<int:pk>/criteria/', ExclusionCriteriaView.as_view(), name='criteria'),
     path('<int:pk>/export/', ExportView.as_view(), name='export'),
     path('<int:pk>/progress/', ProgressView.as_view(), name='progress'),
diff --git a/castellum/recruitment/feeds.py b/castellum/recruitment/feeds.py
index 6b9d52a0ed96d0e1db55f2dcec9ac07ab132ca46..ba9cd5a1491b63c40472de6bb4c2933fe50f87bb 100644
--- a/castellum/recruitment/feeds.py
+++ b/castellum/recruitment/feeds.py
@@ -19,10 +19,12 @@
 # License along with Castellum. If not, see
 # <http://www.gnu.org/licenses/>.
 
-from django.core.exceptions import PermissionDenied
 from django.shortcuts import get_object_or_404
 
 from castellum.appointments.mixins import BaseAppointmentFeed
+from castellum.castellum_auth.mixins import ParamAuthMixin
+from castellum.castellum_auth.mixins import PermissionRequiredMixin
+from castellum.studies.mixins import StudyMixin
 from castellum.studies.models import Resource
 from castellum.studies.models import Study
 
@@ -30,28 +32,21 @@ from .mixins import BaseFollowUpFeed
 from .models import Participation
 
 
-class FollowUpFeedForStudy(BaseFollowUpFeed):
-    def get_object(self, request, *args, **kwargs):
-        study = get_object_or_404(Study, pk=kwargs.get('study_pk'), status=Study.EXECUTION)
-        perms = ['recruitment.recruit', 'studies.access_study']
-        if not self.request.user.has_perms(perms, obj=study):
-            raise PermissionDenied
-        return study
+class FollowUpFeedForStudy(ParamAuthMixin, StudyMixin, PermissionRequiredMixin, BaseFollowUpFeed):
+    permission_required = 'recruitment.recruit'
+    study_status = [Study.EXECUTION]
 
-    def items(self, study):
+    def items(self):
         return Participation.objects\
-            .filter(study=study, followup_date__isnull=False)\
+            .filter(study=self.study, followup_date__isnull=False)\
             .order_by('-followup_date', '-followup_time')
 
 
-class FollowUpFeedForUser(BaseFollowUpFeed):
-    def get_object(self, request, *args, **kwargs):
-        return self.request.user
-
-    def items(self, user):
+class FollowUpFeedForUser(ParamAuthMixin, BaseFollowUpFeed):
+    def items(self):
         perms = ['recruitment.recruit', 'studies.access_study']
         for study in Study.objects.filter(status=Study.EXECUTION):
-            if not user.has_perms(perms, obj=study):
+            if not self.request.user.has_perms(perms, obj=study):
                 continue
             qs = Participation.objects\
                 .filter(study=study, followup_date__isnull=False)\
@@ -60,29 +55,26 @@ class FollowUpFeedForUser(BaseFollowUpFeed):
                 yield participation
 
 
-class AppointmentFeed(BaseAppointmentFeed):
-    def get_object(self, request, *args, **kwargs):
-        study = get_object_or_404(Study, pk=kwargs['pk'], status=Study.EXECUTION)
-        perms = ['appointments.change_appointment', 'studies.access_study']
-        if not self.request.user.has_perms(perms, obj=study):
-            raise PermissionDenied
-        return study
+class AppointmentFeed(ParamAuthMixin, StudyMixin, PermissionRequiredMixin, BaseAppointmentFeed):
+    permission_required = 'appointments.change_appointment'
+    study_status = [Study.EXECUTION]
 
-    def items(self, study):
-        return super().items(study).filter(session__study=study)
+    def items(self):
+        return super().items().filter(session__study=self.study)
 
-    def item_link(self, item):
+    def item_title(self, item):
+        return ''
+
+    def item_uid(self, item):
         # This is not really a usable link, but it is unique
         return '/appointments/{}/'.format(item.pk)
 
 
-class ResourceFeed(BaseAppointmentFeed):
-    def get_object(self, request, *args, **kwargs):
-        return get_object_or_404(Resource, pk=kwargs['pk'])
-
-    def items(self, resource):
+class ResourceFeed(ParamAuthMixin, BaseAppointmentFeed):
+    def items(self):
+        resource = get_object_or_404(Resource, pk=self.kwargs['pk'])
         return (
-            super().items(resource)
+            super().items()
             .filter(session__resource=resource)
             .exclude(session__study__status=Study.FINISHED)
         )
@@ -90,6 +82,6 @@ class ResourceFeed(BaseAppointmentFeed):
     def item_title(self, item):
         return item.session.study.name
 
-    def item_link(self, item):
+    def item_uid(self, item):
         # This is not really a usable link, but it is unique
         return '/appointments/{}/'.format(item.pk)
diff --git a/castellum/recruitment/mixins.py b/castellum/recruitment/mixins.py
index d3e446942366b4e484e0a91ca5a10aa7db46e196..4b3639f18eebe33e6e68174bdce7045ee6370ac1 100644
--- a/castellum/recruitment/mixins.py
+++ b/castellum/recruitment/mixins.py
@@ -40,7 +40,7 @@ from castellum.castellum_auth.mixins import PermissionRequiredMixin
 from castellum.studies.mixins import StudyMixin
 from castellum.subjects.mixins import SubjectMixin
 from castellum.subjects.models import Subject
-from castellum.utils.feeds import BaseICalFeed
+from castellum.utils.feeds import BaseCalendarFeed
 from castellum.utils.mail import MailContext
 
 from . import filter_queries
@@ -146,25 +146,22 @@ class BaseAttributesUpdateView(PermissionRequiredMixin, UpdateView):
         return context
 
 
-class BaseFollowUpFeed(BaseICalFeed):
+class BaseFollowUpFeed(BaseCalendarFeed):
     def item_title(self, item):
         return '{} - Follow-Up'.format(item.study.name)
 
-    def item_start_datetime(self, item):
+    def item_start(self, item):
         if item.followup_time:
             return datetime.datetime.combine(item.followup_date, item.followup_time)
         else:
             return item.followup_date
 
-    def item_updateddate(self, item):
+    def item_updated_at(self, item):
         return item.updated_at
 
     def item_link(self, item):
         return reverse('recruitment:contact', args=[item.study.pk, item.pk])
 
-    def item_description(self, item):
-        return self.request.build_absolute_uri(self.item_link(item))
-
 
 class BaseMailRecruitmentView(StudyMixin, PermissionRequiredMixin, FormView):
     template_name = 'recruitment/mail.html'
diff --git a/castellum/recruitment/urls.py b/castellum/recruitment/urls.py
index 261385b1884fe8c673f78cc8e57a4b36ed8234cb..877ef500c94bc004bad9a8b0306aa38c017f087c 100644
--- a/castellum/recruitment/urls.py
+++ b/castellum/recruitment/urls.py
@@ -44,8 +44,8 @@ from .views import SchedulerPingView
 
 app_name = 'recruitment'
 urlpatterns = [
-    path('followups/', FollowUpFeedForUser(), name='followups-user-feed'),
-    path('resources/<int:pk>/', ResourceFeed(), name='resource-feed'),
+    path('followups/', FollowUpFeedForUser.as_view(), name='followups-user-feed'),
+    path('resources/<int:pk>/', ResourceFeed.as_view(), name='resource-feed'),
     path('scheduler-ping/<int:schedule_id>/<pseudonym>/', SchedulerPingView.as_view()),
     path('<int:study_pk>/', RecruitmentViewOpen.as_view(), name='recruitment-open'),
     path('<int:study_pk>/invited/', RecruitmentViewInvited.as_view(), name='recruitment-invited'),
@@ -67,8 +67,8 @@ urlpatterns = [
     ),
     path('<int:study_pk>/cleanup/', RecruitmentCleanupView.as_view(), name='cleanup'),
     path('<int:pk>/calendar/', CalendarView.as_view(), name='calendar'),
-    path('<int:pk>/calendar/feed/', AppointmentFeed(), name='calendar-feed'),
-    path('<int:study_pk>/followups/', FollowUpFeedForStudy(), name='followups-feed'),
+    path('<int:pk>/calendar/feed/', AppointmentFeed.as_view(), name='calendar-feed'),
+    path('<int:study_pk>/followups/', FollowUpFeedForStudy.as_view(), name='followups-feed'),
     path('<int:study_pk>/<int:pk>/', ContactView.as_view(), name='contact'),
     path(
         '<int:study_pk>/<int:pk>/appointments/',
diff --git a/castellum/utils/feeds.py b/castellum/utils/feeds.py
index 4c32e79212e7e755805bfaa1b2c22b5fb16bb962..078c4c0e95d1bbe7cec225197c1e0e6b8bb49ad4 100644
--- a/castellum/utils/feeds.py
+++ b/castellum/utils/feeds.py
@@ -19,26 +19,45 @@
 # License along with Castellum. If not, see
 # <http://www.gnu.org/licenses/>.
 
-from django.core.exceptions import PermissionDenied
+from django.http import HttpResponse
+from django.utils import timezone
+from django.views.generic import View
 
-from django_ical.views import ICalFeed
-from stronghold.decorators import public
+from icalendar import Calendar
+from icalendar import Event
 
-from castellum.castellum_auth.models import User
 
+class BaseCalendarFeed(View):
+    def get(self, request, **kwargs):
+        cal = Calendar()
+        cal.add('version', '2.0')
+        cal.add('prodid', 'castellum')
 
-@public
-class BaseICalFeed(ICalFeed):
-    def __call__(self, request, *args, **kwargs):
-        self.request = request
-        try:
-            self.request.user = User.objects.get(token=request.GET.get('token'))
-        except User.DoesNotExist:
-            raise PermissionDenied
-        return super().__call__(request, *args, **kwargs)
+        for item in self.items():
+            event = Event()
+            event.add('uid', request.build_absolute_uri(self.item_uid(item)))
+            event.add('dtstamp', self.item_updated_at(item))
+            event.add('summary', self.item_title(item))
+            event.add('dtstart', self.item_start(item))
+            if hasattr(self, 'item_end'):
+                event.add('dtend', self.item_end(item))
+            if hasattr(self, 'item_link'):
+                event.add('url', self._item_link(item))
+            if hasattr(self, 'item_description'):
+                event.add('description', self.item_description(item))
+            elif hasattr(self, 'item_link'):
+                event.add('description', self._item_link(item))
+            cal.add_component(event)
 
-    def item_title(self, item):
-        return None
+        response = HttpResponse(content_type='text/calendar')
+        response.write(cal.to_ical())
+        return response
 
-    def item_description(self, item):
-        return None
+    def item_updated_at(self, item):
+        return timezone.now()
+
+    def item_uid(self, item):
+        return self.item_link(item)
+
+    def _item_link(self, item):
+        return self.request.build_absolute_uri(self.item_link(item))
diff --git a/setup.cfg b/setup.cfg
index f117bf6d5603f1925d16f90153549135fda3fe0b..8732600db003cf7f04ed9046ff1ef80f3e2f1624 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -14,7 +14,6 @@ install_requires =
     cologne-phonetics == 1.3.0
     Django == 3.2.8
     django-bootstrap4 == 3.0.1
-    django-ical == 1.8.0
     django-mfa3 == 0.3.0
     django-npm == 1.0.0
     django-parler == 2.2.0