diff --git a/includes/controller/angeltypes_controller.php b/includes/controller/angeltypes_controller.php
index 28c82fe1..0c8f15fb 100644
--- a/includes/controller/angeltypes_controller.php
+++ b/includes/controller/angeltypes_controller.php
@@ -220,11 +220,12 @@ function angeltype_controller_shiftsFilterDays(AngelType $angeltype)
     $days = [];
     foreach ($all_shifts as $shift) {
         $day = Carbon::make($shift['start'])->format('Y-m-d');
-        if (!in_array($day, $days)) {
-            $days[] = $day;
+        $dayFormatted = Carbon::make($shift['start'])->format(__('Y-m-d'));
+        if (!isset($days[$day])) {
+            $days[$day] = $dayFormatted;
         }
     }
-    sort($days);
+    ksort($days);
     return $days;
 }
 
@@ -244,8 +245,8 @@ function angeltype_controller_shiftsFilter(AngelType $angeltype, $days)
         [$angeltype->id]
     );
     $selected_day = date('Y-m-d');
-    if (!empty($days) && !in_array($selected_day, $days)) {
-        $selected_day = $days[0];
+    if (!empty($days) && !isset($days[$selected_day])) {
+        $selected_day = array_key_first($days);
     }
     if ($request->input('shifts_filter_day')) {
         $selected_day = $request->input('shifts_filter_day');
diff --git a/includes/controller/rooms_controller.php b/includes/controller/rooms_controller.php
index 429a741e..1a253c30 100644
--- a/includes/controller/rooms_controller.php
+++ b/includes/controller/rooms_controller.php
@@ -27,8 +27,8 @@ function room_controller(): array
     $days = [];
     foreach ($all_shifts as $shift) {
         $day = $shift->start->format('Y-m-d');
-        if (!in_array($day, $days)) {
-            $days[] = $day;
+        if (!isset($days[$day])) {
+            $days[$day] = $shift->start->format(__('Y-m-d'));
         }
     }
 
@@ -38,8 +38,8 @@ function room_controller(): array
         AngelType::query()->get('id')->pluck('id')->toArray()
     );
     $selected_day = date('Y-m-d');
-    if (!empty($days) && !in_array($selected_day, $days)) {
-        $selected_day = $days[0];
+    if (!empty($days) && !isset($days[$selected_day])) {
+        $selected_day = array_key_first($days);
     }
     if ($request->input('shifts_filter_day')) {
         $selected_day = $request->input('shifts_filter_day');
diff --git a/includes/controller/shifts_controller.php b/includes/controller/shifts_controller.php
index d6d8e167..b865673b 100644
--- a/includes/controller/shifts_controller.php
+++ b/includes/controller/shifts_controller.php
@@ -273,8 +273,8 @@ function shift_delete_controller()
         error(sprintf(
             __('Do you want to delete the shift %s from %s to %s?'),
             $shift->shiftType->name,
-            $shift->start->format('Y-m-d H:i'),
-            $shift->end->format('H:i')
+            $shift->start->format(__('Y-m-d H:i')),
+            $shift->end->format(__('H:i'))
         ), true),
         form([
             form_hidden('delete_shift', $shift->id),
diff --git a/includes/helper/shift_helper.php b/includes/helper/shift_helper.php
index 1cb8d901..9af7481f 100644
--- a/includes/helper/shift_helper.php
+++ b/includes/helper/shift_helper.php
@@ -41,13 +41,13 @@ class Shift
             (($end->timestamp - $start->timestamp) / 60 / 60)
             * Shifts::getNightShiftMultiplier($start, $end);
         $workLog->comment = sprintf(
-            '%s (%s as %s) in %s, %s - %s',
+            __('%s (%s as %s) in %s, %s - %s'),
             $name,
             $title,
             $type,
             $room->name,
-            $start->format('Y-m-d H:i'),
-            $end->format('Y-m-d H:i')
+            $start->format(__('Y-m-d H:i')),
+            $end->format(__('Y-m-d H:i'))
         );
         $workLog->save();
 
diff --git a/includes/mailer/shifts_mailer.php b/includes/mailer/shifts_mailer.php
index c1eee921..ce037e54 100644
--- a/includes/mailer/shifts_mailer.php
+++ b/includes/mailer/shifts_mailer.php
@@ -36,8 +36,8 @@ function mail_shift_change(Shift $old_shift, Shift $new_shift)
     if ($old_shift->start->timestamp != $new_shift->start->timestamp) {
         $message .= sprintf(
             __('* Shift Start changed from %s to %s'),
-            $old_shift->start->format('Y-m-d H:i'),
-            $new_shift->start->format('Y-m-d H:i')
+            $old_shift->start->format(__('Y-m-d H:i')),
+            $new_shift->start->format(__('Y-m-d H:i'))
         ) . "\n";
         $noticeable_changes = true;
     }
@@ -45,8 +45,8 @@ function mail_shift_change(Shift $old_shift, Shift $new_shift)
     if ($old_shift->end->timestamp != $new_shift->end->timestamp) {
         $message .= sprintf(
             __('* Shift End changed from %s to %s'),
-            $old_shift->end->format('Y-m-d H:i'),
-            $new_shift->end->format('Y-m-d H:i')
+            $old_shift->end->format(__('Y-m-d H:i')),
+            $new_shift->end->format(__('Y-m-d H:i'))
         ) . "\n";
         $noticeable_changes = true;
     }
@@ -66,7 +66,7 @@ function mail_shift_change(Shift $old_shift, Shift $new_shift)
 
     $message .= $new_shift->shiftType->name . "\n";
     $message .= $new_shift->title . "\n";
-    $message .= $new_shift->start->format('Y-m-d H:i') . ' - ' . $new_shift->end->format('H:i') . "\n";
+    $message .= $new_shift->start->format(__('Y-m-d H:i')) . ' - ' . $new_shift->end->format(__('H:i')) . "\n";
     $message .= $new_room->name . "\n\n";
     $message .= url('/shifts', ['action' => 'view', 'shift_id' => $new_shift->id]) . "\n";
 
@@ -94,7 +94,7 @@ function mail_shift_assign(User $user, Shift $shift)
     $message = __('You have been assigned to a Shift:') . "\n";
     $message .= $shift->shiftType->name . "\n";
     $message .= $shift->title . "\n";
-    $message .= $shift->start->format('Y-m-d H:i') . ' - ' . $shift->end->format('H:i') . "\n";
+    $message .= $shift->start->format(__('Y-m-d H:i')) . ' - ' . $shift->end->format(__('H:i')) . "\n";
     $message .= $room->name . "\n\n";
     $message .= url('/shifts', ['action' => 'view', 'shift_id' => $shift->id]) . "\n";
 
@@ -112,7 +112,7 @@ function mail_shift_removed(User $user, Shift $shift)
     $message = __('You have been removed from a Shift:') . "\n";
     $message .= $shift->shiftType->name . "\n";
     $message .= $shift->title . "\n";
-    $message .= $shift->start->format('Y-m-d H:i') . ' - ' . $shift->end->format('H:i') . "\n";
+    $message .= $shift->start->format(__('Y-m-d H:i')) . ' - ' . $shift->end->format(__('H:i')) . "\n";
     $message .= $room->name . "\n";
 
     engelsystem_email_to_user($user, __('Removed from Shift'), $message, true);
diff --git a/includes/pages/admin_arrive.php b/includes/pages/admin_arrive.php
index 5767d818..a4d79017 100644
--- a/includes/pages/admin_arrive.php
+++ b/includes/pages/admin_arrive.php
@@ -115,7 +115,7 @@ function admin_arrive()
         ]);
 
         if ($usr->state->arrival_date) {
-            $day = $usr->state->arrival_date->format('Y-m-d');
+            $day = $usr->state->arrival_date->format(__('Y-m-d'));
             if (!isset($arrival_count_at_day[$day])) {
                 $arrival_count_at_day[$day] = 0;
             }
@@ -123,7 +123,7 @@ function admin_arrive()
         }
 
         if ($usr->personalData->planned_arrival_date) {
-            $day = $usr->personalData->planned_arrival_date->format('Y-m-d');
+            $day = $usr->personalData->planned_arrival_date->format(__('Y-m-d'));
             if (!isset($planned_arrival_count_at_day[$day])) {
                 $planned_arrival_count_at_day[$day] = 0;
             }
@@ -131,7 +131,7 @@ function admin_arrive()
         }
 
         if ($usr->personalData->planned_departure_date && $usr->state->arrived) {
-            $day = $usr->personalData->planned_departure_date->format('Y-m-d');
+            $day = $usr->personalData->planned_departure_date->format(__('Y-m-d'));
             if (!isset($planned_departure_count_at_day[$day])) {
                 $planned_departure_count_at_day[$day] = 0;
             }
diff --git a/includes/pages/admin_shifts.php b/includes/pages/admin_shifts.php
index 2e3cd84e..339d76ce 100644
--- a/includes/pages/admin_shifts.php
+++ b/includes/pages/admin_shifts.php
@@ -304,9 +304,9 @@ function admin_shifts()
                 $shifts_table_entry = [
                     'timeslot'      =>
                         icon('clock-history') . ' '
-                        . $shift['start']->format('Y-m-d H:i')
+                        . $shift['start']->format(__('Y-m-d H:i'))
                         . ' - '
-                        . $shift['end']->format('H:i')
+                        . $shift['end']->format(__('H:i'))
                         . '<br />'
                         . Room_name_render(Room::find($shift['room_id'])),
                     'title'         =>
diff --git a/includes/pages/admin_user.php b/includes/pages/admin_user.php
index a62dce01..b30115e4 100644
--- a/includes/pages/admin_user.php
+++ b/includes/pages/admin_user.php
@@ -54,7 +54,7 @@ function admin_user()
         $html .= '<table>' . "\n";
         $html .= '  <tr><td>' . __('Nickname') . '</td><td>' . '<input size="40" name="eNick" value="' . $user_source->name . '" class="form-control" maxlength="24"></td></tr>' . "\n";
         $html .= '  <tr><td>' . __('Last login') . '</td><td><p class="help-block">'
-            . ($user_source->last_login_at ? $user_source->last_login_at->format('Y-m-d H:i') : '-')
+            . ($user_source->last_login_at ? $user_source->last_login_at->format(__('Y-m-d H:i')) : '-')
             . '</p></td></tr>' . "\n";
         if (config('enable_user_name')) {
             $html .= '  <tr><td>' . __('Prename') . '</td><td>' . '<input size="40" name="eName" value="' . $user_source->personalData->last_name . '" class="form-control" maxlength="64"></td></tr>' . "\n";
diff --git a/includes/pages/user_myshifts.php b/includes/pages/user_myshifts.php
index e031535a..0dbc8823 100644
--- a/includes/pages/user_myshifts.php
+++ b/includes/pages/user_myshifts.php
@@ -96,7 +96,7 @@ function user_myshifts()
 
             return ShiftEntry_edit_view(
                 $shifts_user,
-                $shift->start->format('Y-m-d H:i') . ', ' . shift_length($shift),
+                $shift->start->format(__('Y-m-d H:i')) . ', ' . shift_length($shift),
                 $shift->room->name,
                 $shift->shiftType->name,
                 $shiftEntry->angelType->name,
diff --git a/includes/pages/user_shifts.php b/includes/pages/user_shifts.php
index c32c9d75..127f0270 100644
--- a/includes/pages/user_shifts.php
+++ b/includes/pages/user_shifts.php
@@ -262,6 +262,10 @@ function view_user_shifts()
         info(render_user_arrived_hint());
     }
 
+    $formattedDays = collect($days)->map(function ($value) {
+        return Carbon::make($value)->format(__('Y-m-d'));
+    })->toArray();
+
     return page([
         div('col-md-12', [
             msg(),
@@ -276,14 +280,14 @@ function view_user_shifts()
                 'start_select'  => html_select_key(
                     'start_day',
                     'start_day',
-                    array_combine($days, $days),
+                    array_combine($days, $formattedDays),
                     $start_day
                 ),
                 'start_time'    => $start_time,
                 'end_select'    => html_select_key(
                     'end_day',
                     'end_day',
-                    array_combine($days, $days),
+                    array_combine($days, $formattedDays),
                     $end_day
                 ),
                 'end_time'      => $end_time,
diff --git a/includes/view/ShiftEntry_view.php b/includes/view/ShiftEntry_view.php
index c4d98178..31242b46 100644
--- a/includes/view/ShiftEntry_view.php
+++ b/includes/view/ShiftEntry_view.php
@@ -21,8 +21,8 @@ function ShiftEntry_delete_view_admin(Shift $shift, AngelType $angeltype, User $
             __('Do you want to sign off %s from shift %s from %s to %s as %s?'),
             User_Nick_render($signoff_user),
             $shift->shiftType->name,
-            $shift->start->format('Y-m-d H:i'),
-            $shift->end->format('Y-m-d H:i'),
+            $shift->start->format(__('Y-m-d H:i')),
+            $shift->end->format(__('Y-m-d H:i')),
             $angeltype->name
         ), true),
         form([
@@ -49,8 +49,8 @@ function ShiftEntry_delete_view(Shift $shift, AngelType $angeltype, User $signof
         info(sprintf(
             __('Do you want to sign off from your shift %s from %s to %s as %s?'),
             $shift->shiftType->name,
-            $shift->start->format('Y-m-d H:i'),
-            $shift->end->format('Y-m-d H:i'),
+            $shift->start->format(__('Y-m-d H:i')),
+            $shift->end->format(__('Y-m-d H:i')),
             $angeltype->name
         ), true),
 
diff --git a/includes/view/ShiftsFilterRenderer.php b/includes/view/ShiftsFilterRenderer.php
index f8af0b73..53158003 100644
--- a/includes/view/ShiftsFilterRenderer.php
+++ b/includes/view/ShiftsFilterRenderer.php
@@ -49,12 +49,13 @@ class ShiftsFilterRenderer
         $toolbar = [];
         if ($this->daySelectionEnabled && !empty($this->days)) {
             $selected_day = date('Y-m-d', $this->shiftsFilter->getStartTime());
+            $selected_day_formatted = date(__('Y-m-d'), $this->shiftsFilter->getStartTime());
             $day_dropdown_items = [];
-            foreach ($this->days as $day) {
-                $link = $page_link . '&shifts_filter_day=' . $day;
+            foreach ($this->days as $value => $day) {
+                $link = $page_link . '&shifts_filter_day=' . $value;
                 $day_dropdown_items[] = toolbar_item_link($link, '', $day);
             }
-            $toolbar[] = toolbar_dropdown($selected_day, $day_dropdown_items, true);
+            $toolbar[] = toolbar_dropdown($selected_day_formatted, $day_dropdown_items, true);
 
             if ($dashboardFilter) {
                 $toolbar[] = sprintf(
diff --git a/includes/view/Shifts_view.php b/includes/view/Shifts_view.php
index 8717b9c1..4da95167 100644
--- a/includes/view/Shifts_view.php
+++ b/includes/view/Shifts_view.php
@@ -61,14 +61,14 @@ function Shift_editor_info_render(Shift $shift)
     if (!empty($shift->created_by)) {
         $info[] = sprintf(
             icon('plus-lg') . __('created at %s by %s'),
-            $shift->created_at->format('Y-m-d H:i'),
+            $shift->created_at->format(__('Y-m-d H:i')),
             User_Nick_render($shift->createdBy)
         );
     }
     if (!empty($shift->updated_by)) {
         $info[] = sprintf(
             icon('pencil') . __('edited at %s by %s'),
-            $shift->updated_at->format('Y-m-d H:i'),
+            $shift->updated_at->format(__('Y-m-d H:i')),
             User_Nick_render($shift->updatedBy)
         );
     }
@@ -164,7 +164,7 @@ function Shift_view(Shift $shift, ShiftType $shifttype, Room $room, $angeltypes_
     if (config('signup_advance_hours') && $shift->start->timestamp > time() + config('signup_advance_hours') * 3600) {
         $content[] = info(sprintf(
             __('This shift is in the far future and becomes available for signup at %s.'),
-            date(__('Y-m-d') . ' H:i', $shift->start->timestamp - config('signup_advance_hours') * 3600)
+            date(__('Y-m-d H:i'), $shift->start->timestamp - config('signup_advance_hours') * 3600)
         ), true);
     }
 
diff --git a/includes/view/User_view.php b/includes/view/User_view.php
index c327bdd7..64d67b8e 100644
--- a/includes/view/User_view.php
+++ b/includes/view/User_view.php
@@ -305,10 +305,10 @@ function User_view_myshift(Shift $shift, $user_source, $its_me)
 
     $myshift = [
         'date'       => icon('calendar-event')
-            . $shift->start->format('Y-m-d') . '<br>'
+            . $shift->start->format(__('Y-m-d')) . '<br>'
             . icon('clock-history') . $shift->start->format('H:i')
             . ' - '
-            . $shift->end->format('H:i'),
+            . $shift->end->format(__('H:i')),
         'duration'   => sprintf('%.2f', ($shift->end->timestamp - $shift->start->timestamp) / 3600) . '&nbsp;h',
         'room'       => Room_name_render($shift->room),
         'shift_info' => $shift_info,
@@ -445,7 +445,7 @@ function User_view_worklog(Worklog $worklog, $admin_user_worklog_privilege)
     }
 
     return [
-        'date'       => icon('calendar-event') . date('Y-m-d', $worklog->worked_at->timestamp),
+        'date'       => icon('calendar-event') . date(__('Y-m-d'), $worklog->worked_at->timestamp),
         'duration'   => sprintf('%.2f', $worklog->hours) . ' h',
         'room'       => '',
         'shift_info' => __('Work log entry'),
@@ -453,7 +453,7 @@ function User_view_worklog(Worklog $worklog, $admin_user_worklog_privilege)
             . sprintf(
                 __('Added by %s at %s'),
                 User_Nick_render($worklog->creator),
-                $worklog->created_at->format('Y-m-d H:i')
+                $worklog->created_at->format(__('Y-m-d H:i'))
             ),
         'actions'    => $actions,
     ];
@@ -711,7 +711,7 @@ function User_view_state_admin($freeloader, $user_source)
         $state[] = '<span class="text-success">' . icon('house')
             . sprintf(
                 __('Arrived at %s'),
-                $user_source->state->arrival_date ? $user_source->state->arrival_date->format('Y-m-d') : ''
+                $user_source->state->arrival_date ? $user_source->state->arrival_date->format(__('Y-m-d')) : ''
             )
             . '</span>';
 
@@ -728,7 +728,7 @@ function User_view_state_admin($freeloader, $user_source)
         $state[] = '<span class="text-danger">'
             . ($arrivalDate ? sprintf(
                 __('Not arrived (Planned: %s)'),
-                $arrivalDate->format('Y-m-d')
+                $arrivalDate->format(__('Y-m-d'))
             ) : __('Not arrived'))
             . '</span>';
     }
diff --git a/resources/lang/de_DE/default.po b/resources/lang/de_DE/default.po
index 16f1423b..86466259 100644
--- a/resources/lang/de_DE/default.po
+++ b/resources/lang/de_DE/default.po
@@ -797,6 +797,9 @@ msgid "User %s could not be notified by email due to an error."
 msgstr ""
 "Aufgrund eines Fehlers konnte dem User %s keine E-Mail gesendet werden."
 
+msgid "%s (%s as %s) in %s, %s - %s"
+msgstr "%s (%s als %s) in %s, %s - %s"
+
 #: includes/mailer/shifts_mailer.php:17
 msgid "A Shift you are registered on has changed:"
 msgstr "Eine deiner Schichten hat sich geändert:"
diff --git a/src/Controllers/DesignController.php b/src/Controllers/DesignController.php
index a9935f73..516d9658 100644
--- a/src/Controllers/DesignController.php
+++ b/src/Controllers/DesignController.php
@@ -53,8 +53,9 @@ class DesignController extends BaseController
         $date = CarbonImmutable::now();
 
         for ($i = 1; $i <= 600; $i++) {
-            $formattedDate = $date->format('Y-m-d');
-            $dateSelectOptions[$formattedDate] = $formattedDate;
+            $dateKey = $date->format("Y-m-d");
+            $formattedDisplayDate = $date->format(__("Y-m-d"));
+            $dateSelectOptions[$dateKey] = $formattedDisplayDate;
             $date = $date->addDay();
         }