diff --git a/l10n/de.js b/l10n/de.js
index c126b0e7dfe9f49eb45720b746b0324048a80919..94b4682bd197c4e97af51f41ca8284150b415584 100644
--- a/l10n/de.js
+++ b/l10n/de.js
@@ -584,6 +584,14 @@ OC.L10N.register(
     "Dinner" : "Abendessen",
     "Lunch" : "Mittagessen",
     "Appointment not found" : "Termin nicht gefunden",
-    "User not found" : "Benutzer nicht gefunden"
+    "User not found" : "Benutzer nicht gefunden",
+    "Open Link" : "Link öffnen",
+    "Invitation Tentatively Accepted: %s": "Einladung Vorläufig Angenommen: %s",
+    "Tentatively Accepted": "Vorläufig Angenommen",
+    "Accepted": "Angenommen",
+    "Declined": "Abgelehnt",
+    "%s has declined your invitation to %s on %s" : "%s hat Ihre Einladung zu %s am %s abgelehnt",
+    "%s has accepted your invitation to %s on %s" : "%s hat Ihre Einladung zu %s am %s angenommen",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s hat Ihre Einladung zu %s am %s vorläufig angenommen"
 },
 "nplurals=2; plural=n != 1;");
diff --git a/l10n/de.json b/l10n/de.json
index a6ed5dfed26de72ee843864dba149e9f70ed799f..644db5b2fcdfda918154dca9ba02a79b66a7e0d9 100644
--- a/l10n/de.json
+++ b/l10n/de.json
@@ -582,6 +582,14 @@
     "Dinner" : "Abendessen",
     "Lunch" : "Mittagessen",
     "Appointment not found" : "Termin nicht gefunden",
-    "User not found" : "Benutzer nicht gefunden"
-},"pluralForm" :"nplurals=2; plural=n != 1;"
+    "User not found" : "Benutzer nicht gefunden",
+    "Open Link" : "Link öffnen",
+    "Invitation Tentatively Accepted: %s": "Einladung Vorläufig Angenommen: %s",
+    "Tentatively Accepted": "Vorläufig Angenommen",
+    "Accepted": "Angenommen",
+    "Declined": "Abgelehnt",
+    "%s has declined your invitation to %s on %s" : "%s hat Ihre Einladung zu %s am %s abgelehnt",
+    "%s has accepted your invitation to %s on %s" : "%s hat Ihre Einladung zu %s am %s angenommen",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s hat Ihre Einladung zu %s am %s vorläufig angenommen"
+},"pluralForm" :"nplurals=2; plural=(n != 1);"
 }
\ No newline at end of file
diff --git a/l10n/de_DE.js b/l10n/de_DE.js
index 22a8034cd308a2369265d6dc6278b377447c8fca..16a7c59dcba0d8edc1bec9026da59895fceccb9d 100644
--- a/l10n/de_DE.js
+++ b/l10n/de_DE.js
@@ -584,6 +584,14 @@ OC.L10N.register(
     "Dinner" : "Abendessen",
     "Lunch" : "Mittagessen",
     "Appointment not found" : "Termin nicht gefunden",
-    "User not found" : "Benutzer nicht gefunden"
+    "User not found" : "Benutzer nicht gefunden",
+    "Open Link" : "Link öffnen",
+    "Invitation Tentatively Accepted: %s": "Einladung Vorläufig Angenommen: %s",
+    "Tentatively Accepted": "Vorläufig Angenommen",
+    "Accepted": "Angenommen",
+    "Declined": "Abgelehnt",
+    "%s has declined your invitation to %s on %s" : "%s hat deine Einladung zu %s am %s abgelehnt",
+    "%s has accepted your invitation to %s on %s" : "%s hat deine Einladung zu %s am %s angenommen",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s hat deine Einladung zu %s am %s vorläufig angenommen"
 },
 "nplurals=2; plural=n != 1;");
diff --git a/l10n/de_DE.json b/l10n/de_DE.json
index 58d02fa72a5d59b5c935ece0fe60be542d9ed8a4..ff70df984248702e260540435de729191ed7141c 100644
--- a/l10n/de_DE.json
+++ b/l10n/de_DE.json
@@ -582,6 +582,14 @@
     "Dinner" : "Abendessen",
     "Lunch" : "Mittagessen",
     "Appointment not found" : "Termin nicht gefunden",
-    "User not found" : "Benutzer nicht gefunden"
-},"pluralForm" :"nplurals=2; plural=n != 1;"
+    "User not found" : "Benutzer nicht gefunden",
+    "Open Link" : "Link öffnen",
+    "Invitation Tentatively Accepted: %s": "Einladung Vorläufig Angenommen: %s",
+    "Tentatively Accepted": "Vorläufig Angenommen",
+    "Accepted": "Angenommen",
+    "Declined": "Abgelehnt",
+    "%s has declined your invitation to %s on %s" : "%s hat deine Einladung zu %s am %s abgelehnt",
+    "%s has accepted your invitation to %s on %s" : "%s hat deine Einladung zu %s am %s angenommen",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s hat deine Einladung zu %s am %s vorläufig angenommen"
+},"pluralForm" :"nplurals=2; plural=(n != 1);"
 }
\ No newline at end of file
diff --git a/l10n/en_GB.js b/l10n/en_GB.js
index 1037c903bfbe06fed21413073c3de701280e6f38..6367cfbe14c4149bf0671cb526cc710a93e15bf5 100644
--- a/l10n/en_GB.js
+++ b/l10n/en_GB.js
@@ -80,6 +80,13 @@ OC.L10N.register(
     "Presentation" : "Presentation",
     "Review" : "Review",
     "Office" : "Office",
-    "Mail" : "Mail"
+    "Mail" : "Mail",
+	"Invitation Tentatively Accepted: %s": "Invitation Tentatively Accepted: %s",
+	"Tentatively Accepted": "Tentatively Accepted",
+	"Accepted": "Accepted",
+	"Declined": "Declined",
+	"%s has declined your invitation to %s on %s" : "%s has declined your invitation to %s on %s",
+	"%s has accepted your invitation to %s on %s" : "%s has accepted your invitation to %s on %s",
+	"%s has tentatively accepted your invitation to %s on %s" : "%s has tentatively accepted your invitation to %s on %s"
 },
 "nplurals=2; plural=(n != 1);");
diff --git a/l10n/en_GB.json b/l10n/en_GB.json
index 458687762b8bde8c6b3bb38d675e5e8a61488952..7c863649e8cc0554fb645e822ec5c0dcdfc36da3 100644
--- a/l10n/en_GB.json
+++ b/l10n/en_GB.json
@@ -1,83 +1,90 @@
 { "translations": {
-    "Provided email-address is not valid" : "Provided email address is not valid",
-    "%s has published the calendar »%s«" : "%s has published the calendar »%s«",
-    "Unexpected error sending email. Please contact your administrator." : "Unexpected error sending email. Please contact your administrator.",
-    "Successfully sent email to %1$s" : "Successfully sent email to %1$s",
-    "Hello," : "Hello,",
-    "We wanted to inform you that %s has published the calendar »%s«." : "We wanted to inform you that %s has published the calendar »%s«.",
-    "Open »%s«" : "Open »%s«",
-    "Cheers!" : "Cheers!",
-    "Upcoming events" : "Upcoming events",
-    "Calendar" : "Calendar",
-    "A Calendar app for Nextcloud" : "A Calendar app for Nextcloud",
-    "The Calendar app is a user interface for Nextcloud's CalDAV server. Easily sync events from various devices with your Nextcloud and edit them online.\n\n* 🚀 **Integration with other Nextcloud apps!** Currently Contacts - more to come.\n* 🌐 **WebCal Support!** Want to see your favorite team’s matchdays in your calendar? No problem!\n* 🙋 **Attendees!** Invite people to your events\n* ⌚️ **Free/Busy!** See when your attendees are available to meet\n* ⏰ **Reminders!** Get alarms for events inside your browser and via email\n* 🔍 Search! Find your events at ease\n* ☑️ Tasks! See tasks with a due date directly in the calendar\n* 🙈 **We’re not reinventing the wheel!** Based on the great [c-dav library](https://github.com/nextcloud/cdav-library), [ical.js](https://github.com/mozilla-comm/ical.js) and [fullcalendar](https://github.com/fullcalendar/fullcalendar) libraries." : "The Calendar app is a user interface for Nextcloud's CalDAV server. Easily sync events from various devices with your Nextcloud and edit them online.\n\n* 🚀 **Integration with other Nextcloud apps!** Currently Contacts - more to come.\n* 🌐 **WebCal Support!** Want to see your favorite team’s match days in your calendar? No problem!\n* 🙋 **Attendees!** Invite people to your events.\n* ⌚️ **Free/Busy!** See when your attendees are available to meet.\n* ⏰ **Reminders!** Get alarms for events inside your browser and via email.\n* 🔍 Search! Find your events at ease.\n* ☑️ Tasks! See tasks with a due date directly in the calendar.\n* 🙈 **We’re not reinventing the wheel!** Based on the great [c-dav library](https://github.com/nextcloud/cdav-library), [ical.js](https://github.com/mozilla-comm/ical.js) and [fullcalendar](https://github.com/fullcalendar/fullcalendar) libraries.",
-    "Previous day" : "Previous day",
-    "Previous week" : "Previous week",
-    "Previous month" : "Previous month",
-    "Next day" : "Next day",
-    "Next week" : "Next week",
-    "Next month" : "Next month",
-    "Today" : "Today",
-    "Day" : "Day",
-    "Week" : "Week",
-    "Month" : "Month",
-    "List" : "List",
-    "Delete" : "Delete",
-    "Untitled calendar" : "Untitled calendar",
-    "Edit color" : "Edit colour",
-    "Copy private link" : "Copy private link",
-    "An error occurred, unable to change visibility of the calendar." : "An error occurred, unable to change visibility of the calendar.",
-    "An error occurred, unable to delete the calendar." : "An error occurred, unable to delete the calendar.",
-    "Calendar link copied to clipboard." : "Calendar link copied to clipboard.",
-    "Calendar link could not be copied to clipboard." : "Calendar link could not be copied to clipboard.",
-    "An error occurred, unable to change the calendar's color." : "An error occurred, unable to change the calendar's colour.",
-    "Share link" : "Share link",
-    "Publish calendar" : "Publish calendar",
-    "Publishing calendar" : "Publishing calendar",
-    "Share with users or groups" : "Share with users or groups",
-    "can edit" : "can edit",
-    "New calendar" : "New calendar",
-    "Filename" : "Filename",
-    "Cancel" : "Cancel",
-    "Automatic" : "Automatic",
-    "or" : "or",
-    "Actions" : "Actions",
-    "Show week numbers" : "Show week numbers",
-    "Settings & import" : "Settings & import",
-    "Location" : "Location",
-    "Description" : "Description",
-    "Monday" : "Monday",
-    "Save" : "Save",
-    "Update" : "Update",
-    "Notification" : "Notification",
-    "Email" : "Email",
-    "Busy" : "Busy",
-    "Unknown" : "Unknown",
-    "Tentative" : "Tentative",
-    "All day" : "All day",
-    "Repeat" : "Repeat",
-    "never" : "never",
-    "after" : "after",
-    "More" : "More",
-    "Global" : "Global",
-    "Personal" : "Personal",
-    "Details" : "Details",
-    "Attendees" : "Attendees",
-    "Close" : "Close",
-    "Anniversary" : "Anniversary",
-    "Week {number} of {year}" : "Week {number} of {year}",
-    "Daily" : "Daily",
-    "Weekly" : "Weekly",
-    "When shared show full event" : "When shared show full event",
-    "When shared show only busy" : "When shared show only busy",
-    "When shared hide this event" : "When shared hide this event",
-    "Status" : "Status",
-    "Confirmed" : "Confirmed",
-    "Categories" : "Categories",
-    "Custom color" : "Custom colour",
-    "Presentation" : "Presentation",
-    "Review" : "Review",
-    "Office" : "Office",
-    "Mail" : "Mail"
+  "Provided email-address is not valid" : "Provided email address is not valid",
+  "%s has published the calendar »%s«" : "%s has published the calendar »%s«",
+  "Unexpected error sending email. Please contact your administrator." : "Unexpected error sending email. Please contact your administrator.",
+  "Successfully sent email to %1$s" : "Successfully sent email to %1$s",
+  "Hello," : "Hello,",
+  "We wanted to inform you that %s has published the calendar »%s«." : "We wanted to inform you that %s has published the calendar »%s«.",
+  "Open »%s«" : "Open »%s«",
+  "Cheers!" : "Cheers!",
+  "Upcoming events" : "Upcoming events",
+  "Calendar" : "Calendar",
+  "A Calendar app for Nextcloud" : "A Calendar app for Nextcloud",
+  "The Calendar app is a user interface for Nextcloud's CalDAV server. Easily sync events from various devices with your Nextcloud and edit them online.\n\n* 🚀 **Integration with other Nextcloud apps!** Currently Contacts - more to come.\n* 🌐 **WebCal Support!** Want to see your favorite team’s matchdays in your calendar? No problem!\n* 🙋 **Attendees!** Invite people to your events\n* ⌚️ **Free/Busy!** See when your attendees are available to meet\n* ⏰ **Reminders!** Get alarms for events inside your browser and via email\n* 🔍 Search! Find your events at ease\n* ☑️ Tasks! See tasks with a due date directly in the calendar\n* 🙈 **We’re not reinventing the wheel!** Based on the great [c-dav library](https://github.com/nextcloud/cdav-library), [ical.js](https://github.com/mozilla-comm/ical.js) and [fullcalendar](https://github.com/fullcalendar/fullcalendar) libraries." : "The Calendar app is a user interface for Nextcloud's CalDAV server. Easily sync events from various devices with your Nextcloud and edit them online.\n\n* 🚀 **Integration with other Nextcloud apps!** Currently Contacts - more to come.\n* 🌐 **WebCal Support!** Want to see your favorite team’s match days in your calendar? No problem!\n* 🙋 **Attendees!** Invite people to your events.\n* ⌚️ **Free/Busy!** See when your attendees are available to meet.\n* ⏰ **Reminders!** Get alarms for events inside your browser and via email.\n* 🔍 Search! Find your events at ease.\n* ☑️ Tasks! See tasks with a due date directly in the calendar.\n* 🙈 **We’re not reinventing the wheel!** Based on the great [c-dav library](https://github.com/nextcloud/cdav-library), [ical.js](https://github.com/mozilla-comm/ical.js) and [fullcalendar](https://github.com/fullcalendar/fullcalendar) libraries.",
+  "Previous day" : "Previous day",
+  "Previous week" : "Previous week",
+  "Previous month" : "Previous month",
+  "Next day" : "Next day",
+  "Next week" : "Next week",
+  "Next month" : "Next month",
+  "Today" : "Today",
+  "Day" : "Day",
+  "Week" : "Week",
+  "Month" : "Month",
+  "List" : "List",
+  "Delete" : "Delete",
+  "Untitled calendar" : "Untitled calendar",
+  "Edit color" : "Edit colour",
+  "Copy private link" : "Copy private link",
+  "An error occurred, unable to change visibility of the calendar." : "An error occurred, unable to change visibility of the calendar.",
+  "An error occurred, unable to delete the calendar." : "An error occurred, unable to delete the calendar.",
+  "Calendar link copied to clipboard." : "Calendar link copied to clipboard.",
+  "Calendar link could not be copied to clipboard." : "Calendar link could not be copied to clipboard.",
+  "An error occurred, unable to change the calendar's color." : "An error occurred, unable to change the calendar's colour.",
+  "Share link" : "Share link",
+  "Publish calendar" : "Publish calendar",
+  "Publishing calendar" : "Publishing calendar",
+  "Share with users or groups" : "Share with users or groups",
+  "can edit" : "can edit",
+  "New calendar" : "New calendar",
+  "Filename" : "Filename",
+  "Cancel" : "Cancel",
+  "Automatic" : "Automatic",
+  "or" : "or",
+  "Actions" : "Actions",
+  "Show week numbers" : "Show week numbers",
+  "Settings & import" : "Settings & import",
+  "Location" : "Location",
+  "Description" : "Description",
+  "Monday" : "Monday",
+  "Save" : "Save",
+  "Update" : "Update",
+  "Notification" : "Notification",
+  "Email" : "Email",
+  "Busy" : "Busy",
+  "Unknown" : "Unknown",
+  "Tentative" : "Tentative",
+  "All day" : "All day",
+  "Repeat" : "Repeat",
+  "never" : "never",
+  "after" : "after",
+  "More" : "More",
+  "Global" : "Global",
+  "Personal" : "Personal",
+  "Details" : "Details",
+  "Attendees" : "Attendees",
+  "Close" : "Close",
+  "Anniversary" : "Anniversary",
+  "Week {number} of {year}" : "Week {number} of {year}",
+  "Daily" : "Daily",
+  "Weekly" : "Weekly",
+  "When shared show full event" : "When shared show full event",
+  "When shared show only busy" : "When shared show only busy",
+  "When shared hide this event" : "When shared hide this event",
+  "Status" : "Status",
+  "Confirmed" : "Confirmed",
+  "Categories" : "Categories",
+  "Custom color" : "Custom colour",
+  "Presentation" : "Presentation",
+  "Review" : "Review",
+  "Office" : "Office",
+  "Mail" : "Mail",
+  "Invitation Tentatively Accepted: %s": "Invitation Tentatively Accepted: %s",
+	"Tentatively Accepted": "Tentatively Accepted",
+	"Accepted": "Accepted",
+	"Declined": "Declined",
+	"%s has declined your invitation to %s on %s" : "%s has declined your invitation to %s on %s",
+	"%s has accepted your invitation to %s on %s" : "%s has accepted your invitation to %s on %s",
+	"%s has tentatively accepted your invitation to %s on %s" : "%s has tentatively accepted your invitation to %s on %s"
 },"pluralForm" :"nplurals=2; plural=(n != 1);"
-}
\ No newline at end of file
+}
diff --git a/l10n/es.js b/l10n/es.js
index a79db1b69e88ea6041d195c4615739e53251c8bf..cd83d1e757b6e359bbf7fa28f8d064691a0c11c6 100644
--- a/l10n/es.js
+++ b/l10n/es.js
@@ -567,6 +567,14 @@ OC.L10N.register(
     "Dinner" : "Cena",
     "Lunch" : "Almuerzo",
     "Appointment not found" : "Cita no encontrada",
-    "User not found" : "Usuario no encontrado"
+    "User not found" : "Usuario no encontrado",
+    "Open Link" : "Abrir el enlace",
+    "Invitation Tentatively Accepted: %s": "Invitación Provisionalmente Aceptado: %s",
+    "Tentatively Accepted": "Aceptado Provisionalmente",
+    "Accepted": "Aceptado",
+    "Declined": "Rechazado",
+    "%s has declined your invitation to %s on %s" : "%s ha rechazado tu invitación a %s el %s",
+    "%s has accepted your invitation to %s on %s" : "%s ha aceptado tu invitación a %s el %s",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s ha provisionalmente aceptado tu invitación a %s el %s"
 },
 "nplurals=2; plural=(n != 1);");
diff --git a/l10n/es.json b/l10n/es.json
index 06f4711def478dfc27e9fcd744c21255fc9200bd..7b69fd4ba9caea648347945abe89a985943ca607 100644
--- a/l10n/es.json
+++ b/l10n/es.json
@@ -565,6 +565,14 @@
     "Dinner" : "Cena",
     "Lunch" : "Almuerzo",
     "Appointment not found" : "Cita no encontrada",
-    "User not found" : "Usuario no encontrado"
+    "User not found" : "Usuario no encontrado",
+    "Open Link" : "Abrir el enlace",
+    "Invitation Tentatively Accepted: %s": "Invitación Provisionalmente Aceptado : %s",
+    "Tentatively Accepted": "Aceptado Provisionalmente",
+    "Accepted": "Aceptado",
+    "Declined": "Rechazado",
+    "%s has declined your invitation to %s on %s" : "%s ha rechazado tu invitación a %s el %s",
+    "%s has accepted your invitation to %s on %s" : "%s ha aceptado tu invitación a %s el %s",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s ha provisionalmente aceptado tu invitación a %s el %s"
 },"pluralForm" :"nplurals=2; plural=(n != 1);"
 }
\ No newline at end of file
diff --git a/l10n/fr.js b/l10n/fr.js
index 5571e69f0ce76f0ae46e8ee670e0d4001b2ebe2e..8d300e97c34c0ad5112ca0e6f08481dd078d7ce2 100644
--- a/l10n/fr.js
+++ b/l10n/fr.js
@@ -571,6 +571,14 @@ OC.L10N.register(
     "Dinner" : "Diner",
     "Lunch" : "Repas",
     "Appointment not found" : "Rendez-vous non trouvé",
-    "User not found" : "Utilisateur non trouvé"
+    "User not found" : "Utilisateur non trouvé",
+    "Open Link" : "Ouvrir le lien",
+    "Invitation Tentatively Accepted: %s": "Invitation Accepté Provisoirement: %s",
+	"Tentatively Accepted": "Accepté Provisoirement",
+    "Accepted": "Accepté",
+    "Declined": "Refusé",
+    "%s has declined your invitation to %s on %s" : "%s a refusé votre invitation %s du %s",
+    "%s has accepted your invitation to %s on %s" : "%s a accepté votre invitation %s du %s",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s a provisoirement accepté votre invitation %s du %s"
 },
 "nplurals=2; plural=(n > 1);");
diff --git a/l10n/fr.json b/l10n/fr.json
index 5a0f64f87f3930875aa0eb42bfbfc31a680af4f8..a6d40db2d9f6fa984ec0aad9dde36cca8d86d557 100644
--- a/l10n/fr.json
+++ b/l10n/fr.json
@@ -569,6 +569,14 @@
     "Dinner" : "Diner",
     "Lunch" : "Repas",
     "Appointment not found" : "Rendez-vous non trouvé",
-    "User not found" : "Utilisateur non trouvé"
+    "User not found" : "Utilisateur non trouvé",
+    "Open Link" : "Ouvrir le lien",
+    "Invitation Tentatively Accepted: %s": "Invitation Accepté Provisoirement: %s",
+	"Tentatively Accepted": "Accepté Provisoirement",
+    "Accepted": "Accepté",
+    "Declined": "Refusé",
+	"%s has declined your invitation to %s on %s" : "%s a refusé votre invitation %s du %s",
+    "%s has accepted your invitation to %s on %s" : "%s a accepté votre invitation %s du %s",
+    "%s has tentatively accepted your invitation to %s on %s" : "%s a provisoirement accepté votre invitation %s du %s"
 },"pluralForm" :"nplurals=2; plural=(n > 1);"
 }
\ No newline at end of file
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index e41f2bfacb74646b2db607b9a541ee308330b761..bd2438753f82077a525061986aad7b9f31543b60 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -32,6 +32,20 @@ use OCP\AppFramework\Bootstrap\IBootstrap;
 use OCP\AppFramework\Bootstrap\IRegistrationContext;
 use OCP\User\Events\UserDeletedEvent;
 use function method_exists;
+use OCA\Calendar\Middleware\InvitationMiddleware;
+use OCP\IRequest;
+use OCP\IConfig;
+use \OCP\IDBConnection;
+use \OC\Core\Application as CoreApplication;
+use OCP\Http\Client\IResponse;
+use OCP\Calendar\IManager;
+use OCP\Mail\IMailer;
+use OCP\IL10N;
+use OCP\L10N\IFactory as L10NFactory;
+use OCP\Defaults;
+use OCP\ILogger;
+use OCP\IUserManager;
+
 
 class Application extends App implements IBootstrap {
 
@@ -43,6 +57,53 @@ class Application extends App implements IBootstrap {
 	 */
 	public function __construct(array $params = []) {
 		parent::__construct(self::APP_ID, $params);
+		//$app = new \OCP\AppFramework\App('ecloud-theme-helper');
+		//$containerinvite = $app->getContainer() ;
+		$container = $this->getContainer();
+		/**
+         * Middleware
+         */
+        $container->registerService('InvitationMiddleware', function($c){
+            return new InvitationMiddleware(
+                $c->get(IRequest::class),
+                $c->get(IConfig::class),
+                $c->get(IDBConnection::class),
+                $c->get(IManager::class),
+				$c->get(IMailer::class),
+				$c->get(IL10N::class),
+				$c->get(Defaults::class),
+				$c->get(ILogger::class),
+				$c->get(IUserManager::class),
+				$c->get(L10NFactory::class),
+            );
+        });
+
+        // executed in the order that it is registered
+        $container->registerMiddleware('InvitationMiddleware');
+
+		$app = new \OCP\AppFramework\App('dav');
+		$containerinvite = $app->getContainer() ;
+
+		/**
+         * Middleware
+         */
+        $containerinvite->registerService('InvitationMiddleware', function($c){
+            return new InvitationMiddleware(
+                $c->get(IRequest::class),
+                $c->get(IConfig::class),
+                $c->get(IDBConnection::class),
+                $c->get(IManager::class),
+				$c->get(IMailer::class),
+				$c->get(IL10N::class),
+				$c->get(Defaults::class),
+				$c->get(ILogger::class),
+				$c->get(IUserManager::class),
+				$c->get(L10NFactory::class),
+            );
+        });
+
+		 // executed in the order that it is registered
+		 $containerinvite->registerMiddleware('InvitationMiddleware');
 	}
 
 	/**
@@ -57,11 +118,15 @@ class Application extends App implements IBootstrap {
 		}
 
 		$context->registerEventListener(UserDeletedEvent::class, UserDeletedListener::class);
+
+
 	}
 
 	/**
 	 * @inheritDoc
 	 */
 	public function boot(IBootContext $context): void {
+
+
 	}
-}
+}
\ No newline at end of file
diff --git a/lib/Middleware/InvitationMiddleware.php b/lib/Middleware/InvitationMiddleware.php
new file mode 100644
index 0000000000000000000000000000000000000000..a5058c7087b972c2043c982a17e5c0560bd7f2be
--- /dev/null
+++ b/lib/Middleware/InvitationMiddleware.php
@@ -0,0 +1,229 @@
+<?php
+
+namespace OCA\Calendar\Middleware;
+
+use OCP\AppFramework\Middleware;
+use OCA\Calendar\Controller\InvitationMaybeController;
+use OCA\Dav\Controller\InvitationResponseController;
+use OCP\IDBConnection;
+use OCP\IConfig;
+use OCP\IRequest;
+use OCP\AppFramework\Http\Response;
+use OCP\Calendar\IManager;
+use Sabre\VObject\Reader;
+use OCP\Defaults;
+use OCP\Mail\IMailer;
+use OCP\IL10N;
+use OCP\ILogger;
+use OCP\IUserManager;
+use OCP\IUser;
+use OCP\L10N\IFactory;
+
+class InvitationMiddleware extends Middleware
+{
+	private $request;
+	/** @var IManager */
+	private $calendarManager;
+
+	public function __construct(
+		IRequest $request,
+		IConfig $config,
+		IDBConnection $db,
+		IManager $calendarManager,
+		IMailer $mailer,
+		IL10N $l10n,
+		Defaults $defaults,
+		ILogger $logger,
+		IUserManager $iusermanager,
+		IFactory $languageFactory
+	) {
+		$this->request = $request;
+		$this->config = $config;
+		$this->db = $db;
+		$this->calendarManager = $calendarManager;
+		$this->mailer = $mailer;
+		$this->l10n = $l10n;
+		$this->defaults = $defaults;
+		$this->logger = $logger;
+		$this->iusermanager = $iusermanager;
+		$this->languageFactory = $languageFactory;
+	}
+
+	public function afterController(
+		$controller,
+		$methodName,
+		Response $response
+	) {
+		if (
+			($controller instanceof InvitationMaybeController &&
+				$methodName === "tentative") ||
+			($controller instanceof InvitationResponseController &&
+				($methodName === "accept" || $methodName === "decline") &&
+				$response->getStatus() == 200 &&
+				$response->getTemplateName() == "schedule-response-success")
+		) {
+			$token = $this->request->getParam("token");
+			$query = $this->db->getQueryBuilder();
+			$query
+				->select("*")
+				->from("calendar_invitations")
+				->where(
+					$query
+						->expr()
+						->eq("token", $query->createNamedParameter($token))
+				);
+			$stmt = $query->execute();
+			$row = $stmt->fetch(\PDO::FETCH_ASSOC);
+
+			$uid = $row["uid"];
+			$sender = substr($row["attendee"], 7);
+			$recipient = substr($row["organizer"], 7);
+
+			$query2 = $this->db->getQueryBuilder();
+			$query2
+				->select("*")
+				->from("calendarobjects")
+				->where(
+					$query
+						->expr()
+						->eq("uid", $query2->createNamedParameter($uid))
+				);
+			$stmt2 = $query2->execute();
+			$row2 = $stmt2->fetch(\PDO::FETCH_ASSOC);
+			$calendarobjectid = $row2["id"];
+
+			$query3 = $this->db->getQueryBuilder();
+			$query3
+				->select("*")
+				->from("calendarobjects_props")
+				->where(
+					$query3
+						->expr()
+						->eq(
+							"objectid",
+							$query3->createNamedParameter($calendarobjectid)
+						)
+				);
+			$stmt3 = $query3->execute();
+			$row3 = $stmt3->fetchAll(\PDO::FETCH_ASSOC);
+			foreach ($row3 as $calendarobj1) {
+				if (
+					$calendarobj1["parameter"] == "CN" &&
+					$calendarobj1["name"] == "ATTENDEE"
+				) {
+					$attendeename = $calendarobj1["value"];
+				}
+				if (
+					$calendarobj1["parameter"] == "CN" &&
+					$calendarobj1["name"] == "ORGANIZER"
+				) {
+					$organizername = $calendarobj1["value"];
+				}
+			}
+
+			$vObject = Reader::read($row2["calendardata"]);
+			$SUMMARY = $vObject->VEVENT->SUMMARY;
+			$datestart = (string) $vObject->VEVENT->DTSTART;
+			if (str_contains($datestart, "T")) {
+				$eventdate = date("F d, Y h:i", strtotime($datestart));
+			} else {
+				$eventdate = date("F d, Y", strtotime($datestart));
+			}
+
+			if ($attendeename == "") {
+				$attendeename = $sender;
+			}
+
+			if ($organizername == "") {
+				$organizername = $recipient;
+			}
+
+			$userdata = $this->iusermanager->getByEmail($recipient);
+			$username = $userdata[0]->getUID();
+			$userlang = $this->languageFactory->getUserLanguage($userdata[0]);
+
+			if ($methodName === "tentative") {
+				$meetingTitle = $this->l10n->t("Invitation Tentatively Accepted: %s",	[$SUMMARY]	);
+
+				$data = [
+					"attendee_name" => (string) $sender ?: $defaultVal,
+					"invitee_name" => (string) $recipient ?: $defaultVal,
+					"meeting_title" => (string) $meetingTitle ?: $defaultVal,
+				];
+				$method = "reply";
+				$emailTemplate = $this->mailer->createEMailTemplate(
+					"dav.calendarInvite." . $method,
+					$data
+				);
+				$emailTemplate->setSubject($this->l10n->t("Invitation Tentatively Accepted: %s",[$SUMMARY]));
+				$emailTemplate->addHeader();
+				$emailTemplate->addHeading(
+					$this->l10n->t("Tentatively Accepted")
+				);
+				$mailbodytext = $this->l10n->t(
+					"%s has tentatively accepted your invitation to %s on %s",
+					[$attendeename, $SUMMARY, $eventdate]
+				);
+			}
+
+			if ($methodName === "accept") {
+		    $meetingTitle = $this->l10n->t("Invitation Accepted: %s",	[$SUMMARY]);
+				$data = [
+					"attendee_name" => (string) $sender ?: $defaultVal,
+					"invitee_name" => (string) $recipient ?: $defaultVal,
+					"meeting_title" => (string) $meetingTitle ?: $defaultVal,
+				];
+				$method = "reply";
+				$emailTemplate = $this->mailer->createEMailTemplate(
+					$recipient,
+					$data
+				);
+				$emailTemplate->setSubject($this->l10n->t("Invitation Accepted: %s",	[$SUMMARY]));
+				$emailTemplate->addHeader();
+				$emailTemplate->addHeading($this->l10n->t("Accepted"));
+				$mailbodytext = $this->l10n->t(
+					"%s has accepted your invitation to %s on %s",
+					[$attendeename, $SUMMARY, $eventdate]
+				);
+			}
+
+			if ($methodName === "decline") {
+        $meetingTitle = $this->l10n->t("Invitation Declined: %s",	[$SUMMARY]);
+				$data = [
+					"attendee_name" => (string) $sender ?: $defaultVal,
+					"invitee_name" => (string) $recipient ?: $defaultVal,
+					"meeting_title" => (string) $meetingTitle ?: $defaultVal,
+				];
+				$method = "reply";
+				$emailTemplate = $this->mailer->createEMailTemplate(
+					"dav.calendarInvite." . $method,
+					$data
+				);
+				$emailTemplate->setSubject($this->l10n->t("Invitation Declined: %s",	[$SUMMARY]));
+				$emailTemplate->addHeader();
+				$emailTemplate->addHeading($this->l10n->t("Declined"));
+				$mailbodytext = $this->l10n->t(
+					"%s has declined your invitation to %s on %s",
+					[$attendeename, $SUMMARY, $eventdate]
+				);
+			}
+
+			$emailTemplate->addBodyText(
+				htmlspecialchars($mailbodytext),
+				$mailbodytext
+			);
+			$emailTemplate->addFooter();
+			try {
+				$message = $this->mailer->createMessage();
+				$message->setTo([$recipient => $organizername]);
+				$message->useTemplate($emailTemplate);
+				$this->mailer->send($message);
+			} catch (\Exception $e) {
+				// Log the exception and continue
+				$this->logger->logException($e);
+			}
+		}
+
+		return $response;
+	}
+}