diff --git a/Dockerfile b/Dockerfile
index ea60fd1a2d5903ecb649bfc6fcb81a60a8a7d1a9..6020b6fcacef6e06a8ef794b65174117fed5f52e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -111,6 +111,7 @@ RUN cd ${BASE_DIR} && patch -p0 < ${TMP_PATCH_DIR}/011-privacy-settings.patch
 RUN cd ${BASE_DIR} && patch -u ${BASE_DIR}/apps/dashboard/lib/Controller/DashboardController.php -i ${TMP_PATCH_DIR}/012-remove-user-status-widget.patch
 RUN patch -u ${BASE_DIR}/lib/private/Authentication/Token/PublicKeyTokenProvider.php -i ${TMP_PATCH_DIR}/013-revert-token-password-update.patch
 RUN patch -u ${BASE_DIR}/lib/private/legacy/OC_Helper.php -i ${TMP_PATCH_DIR}/014-add-mail-usage.patch
+RUN cd ${BASE_DIR} && patch -p0 < ${TMP_PATCH_DIR}/015-email-mail-template.patch
 RUN rm -rf ${TMP_PATCH_DIR}
 
 # autocomplete leak tweak apps frontend with sed, disable group suggestion
diff --git a/patches/015-email-mail-template.patch b/patches/015-email-mail-template.patch
new file mode 100644
index 0000000000000000000000000000000000000000..9b88a2151fea2829edfbacc75f6884cb831b4907
--- /dev/null
+++ b/patches/015-email-mail-template.patch
@@ -0,0 +1,33 @@
+--- apps/dav/lib/CalDAV/Schedule/IMipPlugin.php	2022-04-27 09:57:34.955523100 +0530
++++ apps/dav/lib/CalDAV/Schedule/IMipPlugin_Modifiednew.php	2022-04-27 09:57:09.345523100 +0530
+@@ -659,7 +659,7 @@
+ 										Message $iTipMessage, $lastOccurrence) {
+ 		$token = $this->createInvitationToken($iTipMessage, $lastOccurrence);
+ 
+-		$template->addBodyButtonGroup(
++		$template->addBodyButtonGroupTentative(
+ 			$l10n->t('Accept'),
+ 			$this->urlGenerator->linkToRouteAbsolute('dav.invitation_response.accept', [
+ 				'token' => $token,
+@@ -667,18 +667,11 @@
+ 			$l10n->t('Decline'),
+ 			$this->urlGenerator->linkToRouteAbsolute('dav.invitation_response.decline', [
+ 				'token' => $token,
+-			])
++			]),
++			$l10n->t('Maybe'),
++			$this->urlGenerator->getAbsoluteUrl('apps/calendar/invitation/tentative/'.$token)
+ 		);
+ 
+-		$moreOptionsURL = $this->urlGenerator->linkToRouteAbsolute('dav.invitation_response.options', [
+-			'token' => $token,
+-		]);
+-		$html = vsprintf('<small><a href="%s">%s</a></small>', [
+-			$moreOptionsURL, $l10n->t('More options …')
+-		]);
+-		$text = $l10n->t('More options at %s', [$moreOptionsURL]);
+-
+-		$template->addBodyText($html, $text);
+ 	}
+ 
+ 	/**