diff --git a/appinfo/info.xml b/appinfo/info.xml
index 260cb01f7d6..ce507e1f9ae 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -18,7 +18,7 @@
 * 🌉 **Sync with other chat solutions** With [Matterbridge](https://github.com/42wim/matterbridge/) being integrated in Talk, you can easily sync a lot of other chat solutions to Nextcloud Talk and vice-versa.
 ]]></description>
 
-	<version>20.0.0-dev.6</version>
+	<version>20.0.0-dev.7</version>
 	<licence>agpl</licence>
 
 	<author>Daniel Calviño Sánchez</author>
diff --git a/appinfo/routes/routesRoomController.php b/appinfo/routes/routesRoomController.php
index 6921e128079..4687f1ddea3 100644
--- a/appinfo/routes/routesRoomController.php
+++ b/appinfo/routes/routesRoomController.php
@@ -107,5 +107,7 @@
 		['name' => 'Room#setMessageExpiration', 'url' => '/api/{apiVersion}/room/{token}/message-expiration', 'verb' => 'POST', 'requirements' => $requirementsWithToken],
 		/** @see \OCA\Talk\Controller\RoomController::getCapabilities() */
 		['name' => 'Room#getCapabilities', 'url' => '/api/{apiVersion}/room/{token}/capabilities', 'verb' => 'GET', 'requirements' => $requirementsWithToken],
+		/** @see \OCA\Talk\Controller\RoomController::setMentionPermissions() */
+		['name' => 'Room#setMentionPermissions', 'url' => '/api/{apiVersion}/room/{token}/mention-permissions', 'verb' => 'PUT', 'requirements' => $requirementsWithToken],
 	],
 ];
diff --git a/docs/capabilities.md b/docs/capabilities.md
index 9b973cfe88f..16807130597 100644
--- a/docs/capabilities.md
+++ b/docs/capabilities.md
@@ -152,3 +152,4 @@
 
 ## 20
 * `ban-v1` - Whether the API to ban attendees is available
+* `mention-permissions` - Whether non-moderators are allowed to mention `@all`
diff --git a/docs/constants.md b/docs/constants.md
index 5a7520e3328..9b5aaba891c 100644
--- a/docs/constants.md
+++ b/docs/constants.md
@@ -47,6 +47,10 @@
 * `0` Stopped (breakout rooms lobbies are enabled)
 * `1` Started (breakout rooms lobbies are disabled)
 
+### Mention permissions
+* `0` Everyone (default) - All participants can mention using `@all`
+* `1` Moderators - Only moderators can mention using `@all`
+
 ## Participants
 
 ### Participant types
diff --git a/docs/conversation.md b/docs/conversation.md
index 21eca51b43d..e9888b81725 100644
--- a/docs/conversation.md
+++ b/docs/conversation.md
@@ -109,6 +109,7 @@
 | `callStartTime`         | int     | v4    |         | Timestamp when the call was started (only available with `recording-v1` capability)                                                                                                                                                                                                                                                                                                               |
 | `callRecording`         | int     | v4    |         | Type of call recording (see [Constants - Call recording status](constants.md#call-recording-status)) (only available with `recording-v1` capability)                                                                                                                                                                                                                                              |
 | `recordingConsent`      | int     | v4    |         | Whether recording consent is required before joining a call (see [constants list](constants.md#recording-consent-required)) (only available with `recording-consent` capability)                                                                                                                                                                                                                  |
+| `mentionPermissions`    | int     | v4    |         | Whether all participants can mention using `@all` or only moderators (see [constants list](constants.md#mention-permissions)) (only available with `mention-permissions` capability)                                                                                                                                                                                                              |
 
 ## Creating a new conversation
 
@@ -483,6 +484,26 @@ Get all (for moderators and in case of "free selection") or the assigned breakou
         + `403 Forbidden` When the current user is not a moderator/owner or the conversation is not a public conversation
         + `404 Not Found` When the conversation could not be found for the participant
 
+## Set mention permissions
+
+* Required capability: `mention-permissions`
+* Method: `PUT`
+* Endpoint: `/room/{token}/mention-permissions`
+* Data:
+
+| field                | type | Description                                                                                               |
+|----------------------|------|-----------------------------------------------------------------------------------------------------------|
+| `mentionPermissions` | int  | New mention permissions for the conversation (See [mention permssions](constants.md#mention-permissions)) |
+
+* Response:
+	- Status code:
+		+ `200 OK`
+		+ `400 Bad Request` When the conversation type does not support setting mention permissions (only group and public conversation)
+		+ `400 Bad Request` When the conversation is a breakout room
+		+ `400 Bad Request` When permissions value is invalid
+		+ `403 Forbidden` When the current user is not a moderator/owner
+		+ `404 Not Found` When the conversation could not be found for the participant
+
 ## Get conversation capabilities
 
 See [Capability handling in federated conversations](https://github.com/nextcloud/spreed/issues/10680) to learn which capabilities
diff --git a/lib/Capabilities.php b/lib/Capabilities.php
index 904b747e323..e7aca3c0b55 100644
--- a/lib/Capabilities.php
+++ b/lib/Capabilities.php
@@ -100,6 +100,7 @@ class Capabilities implements IPublicCapability {
 		'federation-v1',
 		'ban-v1',
 		'chat-reference-id',
+		'mention-permissions',
 	];
 
 	public const LOCAL_FEATURES = [
diff --git a/lib/Chat/ChatManager.php b/lib/Chat/ChatManager.php
index bfae650db27..1c761d36f9c 100644
--- a/lib/Chat/ChatManager.php
+++ b/lib/Chat/ChatManager.php
@@ -321,11 +321,14 @@ public function sendMessage(
 			}
 		}
 
+		$metadata = [];
 		if ($silent) {
-			$comment->setMetaData([
-				Message::METADATA_SILENT => true,
-			]);
+			$metadata[Message::METADATA_SILENT] = true;
+		}
+		if ($chat->getMentionPermissions() === Room::MENTION_PERMISSIONS_EVERYONE || $participant?->hasModeratorPermissions()) {
+			$metadata[Message::METADATA_CAN_MENTION_ALL] = true;
 		}
+		$comment->setMetaData($metadata);
 
 		$event = new BeforeChatMessageSentEvent($chat, $comment, $participant, $silent, $replyTo);
 		$this->dispatcher->dispatchTyped($event);
@@ -360,7 +363,7 @@ public function sendMessage(
 				}
 			}
 
-			$alreadyNotifiedUsers = $this->notifier->notifyMentionedUsers($chat, $comment, $alreadyNotifiedUsers, $silent);
+			$alreadyNotifiedUsers = $this->notifier->notifyMentionedUsers($chat, $comment, $alreadyNotifiedUsers, $silent, $participant);
 			if (!empty($alreadyNotifiedUsers)) {
 				$userIds = array_column($alreadyNotifiedUsers, 'id');
 				$this->participantService->markUsersAsMentioned($chat, Attendee::ACTOR_USERS, $userIds, (int) $comment->getId(), $usersDirectlyMentioned);
@@ -947,6 +950,10 @@ public function addConversationNotify(array $results, string $search, Room $room
 		if ($room->getType() === Room::TYPE_ONE_TO_ONE) {
 			return $results;
 		}
+		if ($room->getMentionPermissions() === Room::MENTION_PERMISSIONS_MODERATORS && !$participant->hasModeratorPermissions()) {
+			return $results;
+		}
+
 		$attendee = $participant->getAttendee();
 		if ($attendee->getActorType() === Attendee::ACTOR_USERS) {
 			$roomDisplayName = $room->getDisplayName($attendee->getActorId());
diff --git a/lib/Chat/Notifier.php b/lib/Chat/Notifier.php
index e8c4bab0a3b..f32d2dc97c9 100644
--- a/lib/Chat/Notifier.php
+++ b/lib/Chat/Notifier.php
@@ -53,13 +53,17 @@ public function __construct(
 	 * Not every user mentioned in the message is notified, but only those that
 	 * are able to participate in the room.
 	 *
+	 * @param Room $chat
+	 * @param IComment $comment
 	 * @param array[] $alreadyNotifiedUsers
 	 * @psalm-param array<int, array{id: string, type: string, reason: string, sourceId?: string, attendee?: Attendee}> $alreadyNotifiedUsers
+	 * @param bool $silent
+	 * @param Participant|null $participant
 	 * @return string[] Users that were mentioned
 	 * @psalm-return array<int, array{id: string, type: string, reason: string, sourceId?: string, attendee?: Attendee}>
 	 */
-	public function notifyMentionedUsers(Room $chat, IComment $comment, array $alreadyNotifiedUsers, bool $silent): array {
-		$usersToNotify = $this->getUsersToNotify($chat, $comment, $alreadyNotifiedUsers);
+	public function notifyMentionedUsers(Room $chat, IComment $comment, array $alreadyNotifiedUsers, bool $silent, ?Participant $participant = null): array {
+		$usersToNotify = $this->getUsersToNotify($chat, $comment, $alreadyNotifiedUsers, $participant);
 
 		if (!$usersToNotify) {
 			return $alreadyNotifiedUsers;
@@ -102,13 +106,14 @@ public function notifyMentionedUsers(Room $chat, IComment $comment, array $alrea
 	 * @param IComment $comment
 	 * @param array $alreadyNotifiedUsers
 	 * @psalm-param array<int, array{id: string, type: string, reason: string, sourceId?: string, attendee?: Attendee}> $alreadyNotifiedUsers
+	 * @param Participant|null $participant
 	 * @return array
 	 * @psalm-return array<int, array{id: string, type: string, reason: string, sourceId?: string, attendee?: Attendee}>
 	 */
-	public function getUsersToNotify(Room $chat, IComment $comment, array $alreadyNotifiedUsers): array {
+	public function getUsersToNotify(Room $chat, IComment $comment, array $alreadyNotifiedUsers, ?Participant $participant = null): array {
 		$usersToNotify = $this->getMentionedUsers($comment);
 		$usersToNotify = $this->getMentionedGroupMembers($chat, $comment, $usersToNotify);
-		$usersToNotify = $this->addMentionAllToList($chat, $usersToNotify);
+		$usersToNotify = $this->addMentionAllToList($chat, $usersToNotify, $participant);
 		$usersToNotify = $this->removeAlreadyNotifiedUsers($usersToNotify, $alreadyNotifiedUsers);
 
 		return $usersToNotify;
@@ -137,10 +142,11 @@ private function removeAlreadyNotifiedUsers(array $usersToNotify, array $already
 	 * @param Room $chat
 	 * @param array $list
 	 * @psalm-param array<int, array{id: string, type: string, reason: string, sourceId?: string}> $list
+	 * @param Participant|null $participant
 	 * @return array
 	 * @psalm-return array<int, array{id: string, type: string, reason: string, sourceId?: string, attendee?: Attendee}>
 	 */
-	private function addMentionAllToList(Room $chat, array $list): array {
+	private function addMentionAllToList(Room $chat, array $list, ?Participant $participant = null): array {
 		$usersToNotify = array_filter($list, static function (array $entry): bool {
 			return $entry['type'] !== Attendee::ACTOR_USERS || $entry['id'] !== 'all';
 		});
@@ -148,6 +154,9 @@ private function addMentionAllToList(Room $chat, array $list): array {
 		if (count($list) === count($usersToNotify)) {
 			return $usersToNotify;
 		}
+		if ($chat->getMentionPermissions() === Room::MENTION_PERMISSIONS_MODERATORS && (!$participant instanceof Participant || !$participant->hasModeratorPermissions())) {
+			return $usersToNotify;
+		}
 
 		$attendees = $this->participantService->getActorsByType($chat, Attendee::ACTOR_USERS);
 		foreach ($attendees as $attendee) {
diff --git a/lib/Chat/Parser/UserMention.php b/lib/Chat/Parser/UserMention.php
index d1507456b0b..8b181d57315 100644
--- a/lib/Chat/Parser/UserMention.php
+++ b/lib/Chat/Parser/UserMention.php
@@ -90,8 +90,13 @@ protected function parseMessage(Message $chatMessage): void {
 			return mb_strlen($m2['id']) <=> mb_strlen($m1['id']);
 		});
 
+		$metadata = $comment->getMetaData() ?? [];
 		foreach ($mentions as $mention) {
 			if ($mention['type'] === 'user' && $mention['id'] === 'all') {
+				if (!isset($metadata[Message::METADATA_CAN_MENTION_ALL])) {
+					continue;
+				}
+
 				$mention['type'] = 'call';
 			}
 
diff --git a/lib/Controller/RoomController.php b/lib/Controller/RoomController.php
index fe6316abb3b..2b9d7cefbc7 100644
--- a/lib/Controller/RoomController.php
+++ b/lib/Controller/RoomController.php
@@ -1440,6 +1440,28 @@ public function setListable(int $scope): DataResponse {
 		return new DataResponse();
 	}
 
+	/**
+	 * Update the mention permissions for a room
+	 *
+	 * @param 0|1 $mentionPermissions New mention permissions
+	 * @psalm-param Room::MENTION_PERMISSIONS_* $mentionPermissions
+	 * @return DataResponse<Http::STATUS_OK, TalkRoom, array{}>|DataResponse<Http::STATUS_BAD_REQUEST, array<empty>, array{}>
+	 *
+	 * 200: Permissions updated successfully
+	 * 400: Updating permissions is not possible
+	 */
+	#[NoAdminRequired]
+	#[RequireModeratorParticipant]
+	public function setMentionPermissions(int $mentionPermissions): DataResponse {
+		try {
+			$this->roomService->setMentionPermissions($this->room, $mentionPermissions);
+		} catch (\InvalidArgumentException) {
+			return new DataResponse([], Http::STATUS_BAD_REQUEST);
+		}
+
+		return new DataResponse($this->formatRoom($this->room, $this->participant));
+	}
+
 	/**
 	 * Set a password for a room
 	 *
diff --git a/lib/Events/ARoomModifiedEvent.php b/lib/Events/ARoomModifiedEvent.php
index 3fcc1bed8b8..d1e92dc723a 100644
--- a/lib/Events/ARoomModifiedEvent.php
+++ b/lib/Events/ARoomModifiedEvent.php
@@ -29,6 +29,7 @@ abstract class ARoomModifiedEvent extends ARoomEvent {
 	public const PROPERTY_RECORDING_CONSENT = 'recordingConsent';
 	public const PROPERTY_SIP_ENABLED = 'sipEnabled';
 	public const PROPERTY_TYPE = 'type';
+	public const PROPERTY_MENTION_PERMISSIONS = 'mentionPermissions';
 
 	/**
 	 * @param self::PROPERTY_* $property
diff --git a/lib/Manager.php b/lib/Manager.php
index dc9029f38c0..514536abc03 100644
--- a/lib/Manager.php
+++ b/lib/Manager.php
@@ -120,6 +120,7 @@ public function createRoomObjectFromData(array $data): Room {
 			'call_recording' => 0,
 			'recording_consent' => 0,
 			'has_federation' => 0,
+			'mention_permissions' => 0,
 		], $data));
 	}
 
@@ -189,6 +190,7 @@ public function createRoomObject(array $row): Room {
 			(int) $row['call_recording'],
 			(int) $row['recording_consent'],
 			(int) $row['has_federation'],
+			(int) $row['mention_permissions'],
 		);
 	}
 
diff --git a/lib/Migration/Version20000Date20240623123938.php b/lib/Migration/Version20000Date20240623123938.php
new file mode 100644
index 00000000000..e9a7e7afc5a
--- /dev/null
+++ b/lib/Migration/Version20000Date20240623123938.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Talk\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version20000Date20240623123938 extends SimpleMigrationStep {
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure(): ISchemaWrapper $schemaClosure
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$table = $schema->getTable('talk_rooms');
+		if (!$table->hasColumn('mention_permissions')) {
+			$table->addColumn('mention_permissions', Types::INTEGER, [
+				'default' => 0,
+				'notnull' => true,
+			]);
+		}
+
+		return $schema;
+	}
+}
diff --git a/lib/Model/Message.php b/lib/Model/Message.php
index 0beab9513f1..c1407bd2e29 100644
--- a/lib/Model/Message.php
+++ b/lib/Model/Message.php
@@ -23,6 +23,7 @@ class Message {
 	public const METADATA_LAST_EDITED_BY_ID = 'last_edited_by_id';
 	public const METADATA_LAST_EDITED_TIME = 'last_edited_time';
 	public const METADATA_SILENT = 'silent';
+	public const METADATA_CAN_MENTION_ALL = 'can_mention_all';
 
 	/** @var bool */
 	protected $visible = true;
diff --git a/lib/Model/SelectHelper.php b/lib/Model/SelectHelper.php
index 82ef76f0cd0..3dcf3a693ea 100644
--- a/lib/Model/SelectHelper.php
+++ b/lib/Model/SelectHelper.php
@@ -45,6 +45,7 @@ public function selectRoomsTable(IQueryBuilder $query, string $alias = 'r'): voi
 			->addSelect($alias . 'call_recording')
 			->addSelect($alias . 'recording_consent')
 			->addSelect($alias . 'has_federation')
+			->addSelect($alias . 'mention_permissions')
 			->selectAlias($alias . 'id', 'r_id');
 	}
 
diff --git a/lib/ResponseDefinitions.php b/lib/ResponseDefinitions.php
index 781acf78dc8..c1665b45dd3 100644
--- a/lib/ResponseDefinitions.php
+++ b/lib/ResponseDefinitions.php
@@ -246,6 +246,7 @@
  *     listable: int,
  *     lobbyState: int,
  *     lobbyTimer: int,
+ *     mentionPermissions: int,
  *     messageExpiration: int,
  *     name: string,
  *     notificationCalls: int,
diff --git a/lib/Room.php b/lib/Room.php
index 53321ee403d..bba1c88c6a9 100644
--- a/lib/Room.php
+++ b/lib/Room.php
@@ -80,6 +80,9 @@ class Room {
 	public const HAS_FEDERATION_NONE = 0;
 	public const HAS_FEDERATION_TALKv1 = 1;
 
+	public const MENTION_PERMISSIONS_EVERYONE = 0;
+	public const MENTION_PERMISSIONS_MODERATORS = 1;
+
 	protected ?string $currentUser = null;
 	protected ?Participant $participant = null;
 
@@ -124,6 +127,7 @@ public function __construct(
 		private int $callRecording,
 		private int $recordingConsent,
 		private int $hasFederation,
+		private int $mentionPermissions,
 	) {
 	}
 
@@ -559,4 +563,12 @@ public function hasFederatedParticipants(): int {
 	public function setFederatedParticipants(int $hasFederation): void {
 		$this->hasFederation = $hasFederation;
 	}
+
+	public function getMentionPermissions(): int {
+		return $this->mentionPermissions;
+	}
+
+	public function setMentionPermissions(int $mentionPermissions): void {
+		$this->mentionPermissions = $mentionPermissions;
+	}
 }
diff --git a/lib/Service/RoomFormatter.php b/lib/Service/RoomFormatter.php
index 54630f9e0a4..ccad235d61b 100644
--- a/lib/Service/RoomFormatter.php
+++ b/lib/Service/RoomFormatter.php
@@ -139,6 +139,7 @@ public function formatRoomV4(
 			'breakoutRoomMode' => BreakoutRoom::MODE_NOT_CONFIGURED,
 			'breakoutRoomStatus' => BreakoutRoom::STATUS_STOPPED,
 			'recordingConsent' => $this->talkConfig->recordingConsentRequired() === RecordingService::CONSENT_REQUIRED_OPTIONAL ? $room->getRecordingConsent() : $this->talkConfig->recordingConsentRequired(),
+			'mentionPermissions' => Room::MENTION_PERMISSIONS_EVERYONE,
 		];
 
 		$lastActivity = $room->getLastActivity();
@@ -217,6 +218,7 @@ public function formatRoomV4(
 			'messageExpiration' => $room->getMessageExpiration(),
 			'breakoutRoomMode' => $room->getBreakoutRoomMode(),
 			'breakoutRoomStatus' => $room->getBreakoutRoomStatus(),
+			'mentionPermissions' => $room->getMentionPermissions(),
 		]);
 
 		if ($currentParticipant->getAttendee()->getReadPrivacy() === Participant::PRIVACY_PUBLIC) {
diff --git a/lib/Service/RoomService.php b/lib/Service/RoomService.php
index 144f9bc0ef7..2ad9a904394 100644
--- a/lib/Service/RoomService.php
+++ b/lib/Service/RoomService.php
@@ -603,6 +603,44 @@ public function setListable(Room $room, int $newState): bool {
 		return true;
 	}
 
+	/**
+	 * @param Room $room
+	 * @param int $newState New mention permissions from self::MENTION_PERMISSIONS_*
+	 * @throws \InvalidArgumentException When the room type, state or breakout rooms where invalid
+	 */
+	public function setMentionPermissions(Room $room, int $newState): void {
+		$oldState = $room->getMentionPermissions();
+		if ($newState === $oldState) {
+			return;
+		}
+
+		if (!in_array($room->getType(), [Room::TYPE_GROUP, Room::TYPE_PUBLIC], true)) {
+			throw new \InvalidArgumentException('type');
+		}
+
+		if ($room->getObjectType() === BreakoutRoom::PARENT_OBJECT_TYPE) {
+			throw new \InvalidArgumentException('breakout-room');
+		}
+
+		if (!in_array($newState, [Room::MENTION_PERMISSIONS_EVERYONE, Room::MENTION_PERMISSIONS_MODERATORS], true)) {
+			throw new \InvalidArgumentException('state');
+		}
+
+		$event = new BeforeRoomModifiedEvent($room, ARoomModifiedEvent::PROPERTY_MENTION_PERMISSIONS, $newState, $oldState);
+		$this->dispatcher->dispatchTyped($event);
+
+		$update = $this->db->getQueryBuilder();
+		$update->update('talk_rooms')
+			->set('mention_permissions', $update->createNamedParameter($newState, IQueryBuilder::PARAM_INT))
+			->where($update->expr()->eq('id', $update->createNamedParameter($room->getId(), IQueryBuilder::PARAM_INT)));
+		$update->executeStatement();
+
+		$room->setMentionPermissions($newState);
+
+		$event = new RoomModifiedEvent($room, ARoomModifiedEvent::PROPERTY_MENTION_PERMISSIONS, $newState, $oldState);
+		$this->dispatcher->dispatchTyped($event);
+	}
+
 	public function setAssignedSignalingServer(Room $room, ?int $signalingServer): bool {
 		$update = $this->db->getQueryBuilder();
 		$update->update('talk_rooms')
diff --git a/openapi-backend-sipbridge.json b/openapi-backend-sipbridge.json
index b878bb8f9fc..de1b1b96f96 100644
--- a/openapi-backend-sipbridge.json
+++ b/openapi-backend-sipbridge.json
@@ -533,6 +533,7 @@
                     "listable",
                     "lobbyState",
                     "lobbyTimer",
+                    "mentionPermissions",
                     "messageExpiration",
                     "name",
                     "notificationCalls",
@@ -675,6 +676,10 @@
                         "type": "integer",
                         "format": "int64"
                     },
+                    "mentionPermissions": {
+                        "type": "integer",
+                        "format": "int64"
+                    },
                     "messageExpiration": {
                         "type": "integer",
                         "format": "int64"
diff --git a/openapi-federation.json b/openapi-federation.json
index 9b7b96c4372..8b689ea9426 100644
--- a/openapi-federation.json
+++ b/openapi-federation.json
@@ -587,6 +587,7 @@
                     "listable",
                     "lobbyState",
                     "lobbyTimer",
+                    "mentionPermissions",
                     "messageExpiration",
                     "name",
                     "notificationCalls",
@@ -729,6 +730,10 @@
                         "type": "integer",
                         "format": "int64"
                     },
+                    "mentionPermissions": {
+                        "type": "integer",
+                        "format": "int64"
+                    },
                     "messageExpiration": {
                         "type": "integer",
                         "format": "int64"
diff --git a/openapi-full.json b/openapi-full.json
index 7fe5f42df82..f3c96085ebc 100644
--- a/openapi-full.json
+++ b/openapi-full.json
@@ -1097,6 +1097,7 @@
                     "listable",
                     "lobbyState",
                     "lobbyTimer",
+                    "mentionPermissions",
                     "messageExpiration",
                     "name",
                     "notificationCalls",
@@ -1239,6 +1240,10 @@
                         "type": "integer",
                         "format": "int64"
                     },
+                    "mentionPermissions": {
+                        "type": "integer",
+                        "format": "int64"
+                    },
                     "messageExpiration": {
                         "type": "integer",
                         "format": "int64"
@@ -14752,6 +14757,130 @@
                 }
             }
         },
+        "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mention-permissions": {
+            "put": {
+                "operationId": "room-set-mention-permissions",
+                "summary": "Update the mention permissions for a room",
+                "tags": [
+                    "room"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "parameters": [
+                    {
+                        "name": "mentionPermissions",
+                        "in": "query",
+                        "description": "New mention permissions",
+                        "required": true,
+                        "schema": {
+                            "type": "integer",
+                            "format": "int64",
+                            "enum": [
+                                0,
+                                1
+                            ]
+                        }
+                    },
+                    {
+                        "name": "apiVersion",
+                        "in": "path",
+                        "required": true,
+                        "schema": {
+                            "type": "string",
+                            "enum": [
+                                "v4"
+                            ],
+                            "default": "v4"
+                        }
+                    },
+                    {
+                        "name": "token",
+                        "in": "path",
+                        "required": true,
+                        "schema": {
+                            "type": "string",
+                            "pattern": "^[a-z0-9]{4,30}$"
+                        }
+                    },
+                    {
+                        "name": "OCS-APIRequest",
+                        "in": "header",
+                        "description": "Required to be true for the API request to pass",
+                        "required": true,
+                        "schema": {
+                            "type": "boolean",
+                            "default": true
+                        }
+                    }
+                ],
+                "responses": {
+                    "200": {
+                        "description": "Permissions updated successfully",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {
+                                                    "$ref": "#/components/schemas/Room"
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "400": {
+                        "description": "Updating permissions is not possible",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        },
         "/ocs/v2.php/apps/spreed/api/{apiVersion}/settings/user": {
             "post": {
                 "operationId": "settings-set-user-setting",
diff --git a/openapi.json b/openapi.json
index 241e53ff097..790fac8963e 100644
--- a/openapi.json
+++ b/openapi.json
@@ -984,6 +984,7 @@
                     "listable",
                     "lobbyState",
                     "lobbyTimer",
+                    "mentionPermissions",
                     "messageExpiration",
                     "name",
                     "notificationCalls",
@@ -1126,6 +1127,10 @@
                         "type": "integer",
                         "format": "int64"
                     },
+                    "mentionPermissions": {
+                        "type": "integer",
+                        "format": "int64"
+                    },
                     "messageExpiration": {
                         "type": "integer",
                         "format": "int64"
@@ -14862,6 +14867,130 @@
                 }
             }
         },
+        "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mention-permissions": {
+            "put": {
+                "operationId": "room-set-mention-permissions",
+                "summary": "Update the mention permissions for a room",
+                "tags": [
+                    "room"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "parameters": [
+                    {
+                        "name": "mentionPermissions",
+                        "in": "query",
+                        "description": "New mention permissions",
+                        "required": true,
+                        "schema": {
+                            "type": "integer",
+                            "format": "int64",
+                            "enum": [
+                                0,
+                                1
+                            ]
+                        }
+                    },
+                    {
+                        "name": "apiVersion",
+                        "in": "path",
+                        "required": true,
+                        "schema": {
+                            "type": "string",
+                            "enum": [
+                                "v4"
+                            ],
+                            "default": "v4"
+                        }
+                    },
+                    {
+                        "name": "token",
+                        "in": "path",
+                        "required": true,
+                        "schema": {
+                            "type": "string",
+                            "pattern": "^[a-z0-9]{4,30}$"
+                        }
+                    },
+                    {
+                        "name": "OCS-APIRequest",
+                        "in": "header",
+                        "description": "Required to be true for the API request to pass",
+                        "required": true,
+                        "schema": {
+                            "type": "boolean",
+                            "default": true
+                        }
+                    }
+                ],
+                "responses": {
+                    "200": {
+                        "description": "Permissions updated successfully",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {
+                                                    "$ref": "#/components/schemas/Room"
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "400": {
+                        "description": "Updating permissions is not possible",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        },
         "/ocs/v2.php/apps/spreed/api/{apiVersion}/settings/user": {
             "post": {
                 "operationId": "settings-set-user-setting",
diff --git a/src/components/ConversationSettings/ConversationSettingsDialog.vue b/src/components/ConversationSettings/ConversationSettingsDialog.vue
index 782e9b86917..ef9bc0fa792 100644
--- a/src/components/ConversationSettings/ConversationSettingsDialog.vue
+++ b/src/components/ConversationSettings/ConversationSettingsDialog.vue
@@ -37,6 +37,7 @@
 			<NcAppSettingsSection id="conversation-settings"
 				:name="selfIsOwnerOrModerator ? t('spreed', 'Moderation') : t('spreed', 'Setup overview')">
 				<ListableSettings v-if="!isNoteToSelf && !isGuest" :token="token" :can-moderate="canFullModerate" />
+				<MentionsSettings v-if="!isNoteToSelf" :token="token" :can-moderate="canFullModerate" />
 				<LinkShareSettings v-if="!isNoteToSelf" :token="token" :can-moderate="canFullModerate" />
 				<RecordingConsentSettings v-if="!isNoteToSelf && recordingConsentAvailable" :token="token" :can-moderate="selfIsOwnerOrModerator" />
 				<ExpirationSettings :token="token" :can-moderate="selfIsOwnerOrModerator" />
@@ -113,6 +114,7 @@ import ListableSettings from './ListableSettings.vue'
 import LobbySettings from './LobbySettings.vue'
 import LockingSettings from './LockingSettings.vue'
 import MatterbridgeSettings from './Matterbridge/MatterbridgeSettings.vue'
+import MentionsSettings from './MentionsSettings.vue'
 import NotificationsSettings from './NotificationsSettings.vue'
 import RecordingConsentSettings from './RecordingConsentSettings.vue'
 import SipSettings from './SipSettings.vue'
@@ -137,6 +139,7 @@ export default {
 		LobbySettings,
 		LockingSettings,
 		MatterbridgeSettings,
+		MentionsSettings,
 		NcAppSettingsDialog,
 		NcAppSettingsSection,
 		NcCheckboxRadioSwitch,
diff --git a/src/components/ConversationSettings/MentionsSettings.vue b/src/components/ConversationSettings/MentionsSettings.vue
new file mode 100644
index 00000000000..486bc3386a2
--- /dev/null
+++ b/src/components/ConversationSettings/MentionsSettings.vue
@@ -0,0 +1,136 @@
+<!--
+  - SPDX-FileCopyrightText: 2020 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
+<template>
+	<div v-if="canModerate">
+		<NcCheckboxRadioSwitch :checked="mentionPermissions === MENTION_PERMISSIONS.EVERYONE"
+			:disabled="isMentionPermissionsLoading"
+			type="switch"
+			@update:checked="toggleMentionPermissions">
+			{{ t('spreed', 'Allow participants to mention @all') }}
+		</NcCheckboxRadioSwitch>
+	</div>
+
+	<div v-else>
+		<h5 class="app-settings-section__subtitle">
+			{{ t('spreed', 'Mention permissions') }}
+		</h5>
+		<p>{{ summaryLabel }}</p>
+	</div>
+</template>
+
+<script>
+import { showError, showSuccess } from '@nextcloud/dialogs'
+import { t } from '@nextcloud/l10n'
+
+import NcCheckboxRadioSwitch from '@nextcloud/vue/dist/Components/NcCheckboxRadioSwitch.js'
+
+import { CONVERSATION } from '../../constants.js'
+
+export default {
+	name: 'MentionsSettings',
+
+	components: {
+		NcCheckboxRadioSwitch,
+	},
+
+	props: {
+		token: {
+			type: String,
+			default: null,
+		},
+
+		canModerate: {
+			type: Boolean,
+			default: true,
+		},
+	},
+
+	setup() {
+		const { MENTION_PERMISSIONS } = CONVERSATION
+		return {
+			MENTION_PERMISSIONS,
+		}
+	},
+
+	data() {
+		return {
+			mentionPermissions: null,
+			isMentionPermissionsLoading: false,
+			lastNotification: null,
+		}
+	},
+
+	computed: {
+		conversation() {
+			return this.$store.getters.conversation(this.token) || this.$store.getters.dummyConversation
+		},
+
+		summaryLabel() {
+			switch (this.mentionPermissions) {
+			case CONVERSATION.MENTION_PERMISSIONS.MODERATORS:
+				return t('spreed', 'Only moderators are allowed to mention @all')
+			case CONVERSATION.MENTION_PERMISSIONS.EVERYONE:
+			default:
+				return t('spreed', 'All participants are allowed to mention @all')
+			}
+		}
+	},
+
+	watch: {
+		conversation: {
+			immediate: true,
+			handler() {
+				this.mentionPermissions = this.conversation.mentionPermissions
+			},
+		},
+	},
+
+	beforeDestroy() {
+		if (this.lastNotification) {
+			this.lastNotification.hideToast()
+			this.lastNotification = null
+		}
+	},
+
+	methods: {
+		t,
+		async toggleMentionPermissions(checked) {
+			const mentionPermissions = checked ? this.MENTION_PERMISSIONS.EVERYONE : this.MENTION_PERMISSIONS.MODERATORS
+			if (!this.token) {
+				this.mentionPermissions = mentionPermissions
+				return
+			}
+			this.isMentionPermissionsLoading = true
+			try {
+				await this.$store.dispatch('setMentionPermissions', {
+					token: this.token,
+					mentionPermissions,
+				})
+
+				if (this.lastNotification) {
+					this.lastNotification.hideToast()
+					this.lastNotification = null
+				}
+				if (mentionPermissions === CONVERSATION.MENTION_PERMISSIONS.EVERYONE) {
+					this.lastNotification = showSuccess(t('spreed', 'Participants are now allowed to mention @all.'))
+				} else if (mentionPermissions === CONVERSATION.MENTION_PERMISSIONS.MODERATORS) {
+					this.lastNotification = showSuccess(t('spreed', 'Mentioning @all has been limited to moderators.'))
+				}
+				this.mentionPermissions = mentionPermissions
+			} catch (e) {
+				console.error('Error occurred when opening or limiting the conversation', e)
+				showError(t('spreed', 'Error occurred when opening or limiting the conversation'))
+				this.mentionPermissions = this.conversation.mentionPermissions
+			}
+			this.isMentionPermissionsLoading = false
+		},
+	},
+
+}
+</script>
+
+<style lang="scss" scoped>
+</style>
diff --git a/src/constants.js b/src/constants.js
index 6d617d5736b..992c77bc3bb 100644
--- a/src/constants.js
+++ b/src/constants.js
@@ -56,6 +56,11 @@ export const CONVERSATION = {
 		ALL: 2,
 	},
 
+	MENTION_PERMISSIONS: {
+		EVERYONE: 0,
+		MODERATORS: 1,
+	},
+
 	TYPE: {
 		ONE_TO_ONE: 1,
 		GROUP: 2,
diff --git a/src/services/conversationsService.js b/src/services/conversationsService.js
index c2fc37cf0a8..b565f942566 100644
--- a/src/services/conversationsService.js
+++ b/src/services/conversationsService.js
@@ -306,6 +306,12 @@ const changeListable = async function(token, listable) {
 	})
 }
 
+const setMentionPermissions = async function(token, mentionPermissions) {
+	return axios.put(generateOcsUrl('apps/spreed/api/v4/room/{token}/mention-permissions', { token }), {
+		mentionPermissions,
+	})
+}
+
 /**
  * Set the default permissions for participants in a conversation.
  *
@@ -375,4 +381,5 @@ export {
 	setConversationPermissions,
 	setCallPermissions,
 	setMessageExpiration,
+	setMentionPermissions,
 }
diff --git a/src/store/conversationsStore.js b/src/store/conversationsStore.js
index febdd3db5c9..295ec7d94cf 100644
--- a/src/store/conversationsStore.js
+++ b/src/store/conversationsStore.js
@@ -46,6 +46,7 @@ import {
 	setConversationPassword,
 	createPublicConversation,
 	createPrivateConversation,
+	setMentionPermissions,
 } from '../services/conversationsService.js'
 import {
 	clearConversationHistory,
@@ -75,6 +76,7 @@ const DUMMY_CONVERSATION = {
 	participantType: PARTICIPANT.TYPE.USER,
 	readOnly: CONVERSATION.STATE.READ_ONLY,
 	listable: CONVERSATION.LISTABLE.NONE,
+	mentions: CONVERSATION.MENTION_PERMISSIONS.EVERYONE,
 	hasCall: false,
 	canStartCall: false,
 	lobbyState: WEBINAR.LOBBY.NONE,
@@ -228,6 +230,10 @@ const mutations = {
 		Vue.set(state.conversations[token], 'callPermissions', permissions)
 	},
 
+	setMentionPermissions(state, { token, mentionPermissions }) {
+		Vue.set(state.conversations[token], 'mentionPermissions', mentionPermissions)
+	},
+
 	setCallRecording(state, { token, callRecording }) {
 		Vue.set(state.conversations[token], 'callRecording', callRecording)
 	},
@@ -975,6 +981,15 @@ const actions = {
 		}
 	},
 
+	async setMentionPermissions(context, { token, mentionPermissions }) {
+		try {
+			await setMentionPermissions(token, mentionPermissions)
+			context.commit('setMentionPermissions', { token, mentionPermissions })
+		} catch (error) {
+			console.error('Error while updating mention permissions: ', error)
+		}
+	},
+
 	async startCallRecording(context, { token, callRecording }) {
 		try {
 			await startCallRecording(token, callRecording)
diff --git a/src/types/openapi/openapi-backend-sipbridge.ts b/src/types/openapi/openapi-backend-sipbridge.ts
index 37500bdd847..60fea67f2de 100644
--- a/src/types/openapi/openapi-backend-sipbridge.ts
+++ b/src/types/openapi/openapi-backend-sipbridge.ts
@@ -294,6 +294,8 @@ export type components = {
             /** Format: int64 */
             lobbyTimer: number;
             /** Format: int64 */
+            mentionPermissions: number;
+            /** Format: int64 */
             messageExpiration: number;
             name: string;
             /** Format: int64 */
diff --git a/src/types/openapi/openapi-federation.ts b/src/types/openapi/openapi-federation.ts
index 10f6282a268..b558303de44 100644
--- a/src/types/openapi/openapi-federation.ts
+++ b/src/types/openapi/openapi-federation.ts
@@ -337,6 +337,8 @@ export type components = {
             /** Format: int64 */
             lobbyTimer: number;
             /** Format: int64 */
+            mentionPermissions: number;
+            /** Format: int64 */
             messageExpiration: number;
             name: string;
             /** Format: int64 */
diff --git a/src/types/openapi/openapi-full.ts b/src/types/openapi/openapi-full.ts
index 63fc2217721..b1412694208 100644
--- a/src/types/openapi/openapi-full.ts
+++ b/src/types/openapi/openapi-full.ts
@@ -1183,6 +1183,23 @@ export type paths = {
         patch?: never;
         trace?: never;
     };
+    "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mention-permissions": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        /** Update the mention permissions for a room */
+        put: operations["room-set-mention-permissions"];
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/ocs/v2.php/apps/spreed/api/{apiVersion}/settings/user": {
         parameters: {
             query?: never;
@@ -2087,6 +2104,8 @@ export type components = {
             /** Format: int64 */
             lobbyTimer: number;
             /** Format: int64 */
+            mentionPermissions: number;
+            /** Format: int64 */
             messageExpiration: number;
             name: string;
             /** Format: int64 */
@@ -7328,6 +7347,54 @@ export interface operations {
             };
         };
     };
+    "room-set-mention-permissions": {
+        parameters: {
+            query: {
+                /** @description New mention permissions */
+                mentionPermissions: 0 | 1;
+            };
+            header: {
+                /** @description Required to be true for the API request to pass */
+                "OCS-APIRequest": boolean;
+            };
+            path: {
+                apiVersion: "v4";
+                token: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description Permissions updated successfully */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: components["schemas"]["Room"];
+                        };
+                    };
+                };
+            };
+            /** @description Updating permissions is not possible */
+            400: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: unknown;
+                        };
+                    };
+                };
+            };
+        };
+    };
     "settings-set-user-setting": {
         parameters: {
             query: {
diff --git a/src/types/openapi/openapi.ts b/src/types/openapi/openapi.ts
index 0f7fdedff7c..4f36d9b9ef2 100644
--- a/src/types/openapi/openapi.ts
+++ b/src/types/openapi/openapi.ts
@@ -1185,6 +1185,23 @@ export type paths = {
         patch?: never;
         trace?: never;
     };
+    "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mention-permissions": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        /** Update the mention permissions for a room */
+        put: operations["room-set-mention-permissions"];
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/ocs/v2.php/apps/spreed/api/{apiVersion}/settings/user": {
         parameters: {
             query?: never;
@@ -1572,6 +1589,8 @@ export type components = {
             /** Format: int64 */
             lobbyTimer: number;
             /** Format: int64 */
+            mentionPermissions: number;
+            /** Format: int64 */
             messageExpiration: number;
             name: string;
             /** Format: int64 */
@@ -6906,6 +6925,54 @@ export interface operations {
             };
         };
     };
+    "room-set-mention-permissions": {
+        parameters: {
+            query: {
+                /** @description New mention permissions */
+                mentionPermissions: 0 | 1;
+            };
+            header: {
+                /** @description Required to be true for the API request to pass */
+                "OCS-APIRequest": boolean;
+            };
+            path: {
+                apiVersion: "v4";
+                token: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description Permissions updated successfully */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: components["schemas"]["Room"];
+                        };
+                    };
+                };
+            };
+            /** @description Updating permissions is not possible */
+            400: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: unknown;
+                        };
+                    };
+                };
+            };
+        };
+    };
     "settings-set-user-setting": {
         parameters: {
             query: {
diff --git a/tests/integration/features/bootstrap/FeatureContext.php b/tests/integration/features/bootstrap/FeatureContext.php
index ea13b2a903a..9cd7513e2fa 100644
--- a/tests/integration/features/bootstrap/FeatureContext.php
+++ b/tests/integration/features/bootstrap/FeatureContext.php
@@ -4627,6 +4627,31 @@ public function sendXMLRequest($verb, $url, $body = null, array $headers = [], a
 		$this->sendRequestFullUrl($verb, $fullUrl, $body, $headers, $options);
 	}
 
+	/**
+	 * @When /^user "([^"]*)" sets mention permissions for room "([^"]*)" to (all|moderators) with (\d+) \((v4)\)$/
+	 *
+	 * @param string $user
+	 * @param string $identifier
+	 * @param string $mentionPermissions
+	 * @param int $statusCode
+	 * @param string $apiVersion
+	 */
+	public function userSetsMentionPermissionsOfTheRoom(string $user, string $identifier, string $mentionPermissions, int $statusCode, string $apiVersion): void {
+		$intMentionPermissions = 0; // all - default
+		if($mentionPermissions === 'moderators') {
+			$intMentionPermissions = 1;
+		}
+
+		$this->setCurrentUser($user);
+		$this->sendRequest(
+			'PUT', '/apps/spreed/api/' . $apiVersion . '/room/' . self::$identifierToToken[$identifier] . '/mention-permissions',
+			new TableNode([
+				['mentionPermissions', $intMentionPermissions],
+			])
+		);
+		$this->assertStatusCode($this->response, $statusCode);
+	}
+
 	/**
 	 * @param string $verb
 	 * @param string $url
diff --git a/tests/integration/features/chat-1/mentions.feature b/tests/integration/features/chat-1/mentions.feature
index efb32e32efd..c3140dddf35 100644
--- a/tests/integration/features/chat-1/mentions.feature
+++ b/tests/integration/features/chat-1/mentions.feature
@@ -633,3 +633,25 @@ Feature: chat/mentions
     Then user "participant1" sees the following messages in room "participant1-note-to-self" with 200
       | room                      | actorType | actorId      | actorDisplayName         | message                | messageParameters |
       | participant1-note-to-self | users     | participant1 | participant1-displayname | Test {mention-call1}   | "IGNORE"          |
+
+  Scenario: get mentions with different mention permissions available
+    Given user "participant1" creates room "group room" (v4)
+      | roomType | 2 |
+      | roomName | room |
+    And user "participant1" adds user "participant2" to room "group room" with 200 (v4)
+    Then user "participant1" gets the following candidate mentions in room "group room" for "" with 200
+      | id           | label                    | source | mentionId    |
+      | all          | room                     | calls  | all          |
+      | participant2 | participant2-displayname | users  | participant2 |
+    And user "participant2" gets the following candidate mentions in room "group room" for "" with 200
+      | id           | label                    | source | mentionId    |
+      | all          | room                     | calls  | all          |
+      | participant1 | participant1-displayname | users  | participant1 |
+    When user "participant1" sets mention permissions for room "group room" to moderators with 200 (v4)
+    Then user "participant1" gets the following candidate mentions in room "group room" for "" with 200
+      | id           | label                    | source | mentionId    |
+      | all          | room                     | calls  | all          |
+      | participant2 | participant2-displayname | users  | participant2 |
+    And user "participant2" gets the following candidate mentions in room "group room" for "" with 200
+      | id           | label                    | source | mentionId    |
+      | participant1 | participant1-displayname | users  | participant1 |
diff --git a/tests/integration/features/chat-1/notifications.feature b/tests/integration/features/chat-1/notifications.feature
index e74482e1d8c..e29accc663d 100644
--- a/tests/integration/features/chat-1/notifications.feature
+++ b/tests/integration/features/chat-1/notifications.feature
@@ -544,3 +544,18 @@ Feature: chat/notifications
     When user "participant1" sets lobby state for room "room" to "non moderators" with 200 (v4)
     Then user "participant2" has the following notifications
       | app | object_type | object_id | subject |
+
+  Scenario: At-all with different mention permissions
+    Given user "participant1" creates room "room" (v4)
+      | roomType | 2 |
+      | roomName | room |
+    And user "participant1" adds user "participant2" to room "room" with 200 (v4)
+    When user "participant2" sends message "Hi @all" to room "room" with 201
+    Then user "participant1" has the following notifications
+      | app    | object_type | object_id       | subject                                                          |
+      | spreed | chat        | room/Hi @all    | participant2-displayname mentioned everyone in conversation room |
+    When user "participant1" reads message "Hi @all" in room "room" with 200
+    And user "participant1" sets mention permissions for room "room" to moderators with 200 (v4)
+    And user "participant2" sends message "Hi @all" to room "room" with 201
+    Then user "participant1" has the following notifications
+      | app | object_type | object_id | subject |
diff --git a/tests/php/Chat/ChatManagerTest.php b/tests/php/Chat/ChatManagerTest.php
index 05444b0a43b..6160e01b8c9 100644
--- a/tests/php/Chat/ChatManagerTest.php
+++ b/tests/php/Chat/ChatManagerTest.php
@@ -694,38 +694,56 @@ public static function dataAddConversationNotify(): array {
 			],
 			[
 				'',
-				['getDisplayName' => 'test'],
+				['getDisplayName' => 'test', 'getMentionPermissions' => 0],
 				['getAttendee' => Attendee::fromRow([
 					'actor_type' => Attendee::ACTOR_USERS,
 					'actor_id' => 'user',
 				])],
 				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
 			],
+			[
+				'',
+				['getMentionPermissions' => 1],
+				['hasModeratorPermissions' => false],
+				[]
+			],
 			[
 				'all',
-				['getDisplayName' => 'test'],
+				['getDisplayName' => 'test', 'getMentionPermissions' => 0],
 				['getAttendee' => Attendee::fromRow([
 					'actor_type' => Attendee::ACTOR_USERS,
 					'actor_id' => 'user',
 				])],
 				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
 			],
+			[
+				'all',
+				['getDisplayName' => 'test', 'getMentionPermissions' => 1],
+				[
+					'getAttendee' => Attendee::fromRow([
+						'actor_type' => Attendee::ACTOR_USERS,
+						'actor_id' => 'user',
+					]),
+					'hasModeratorPermissions' => true,
+				],
+				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
+			],
 			[
 				'here',
-				['getDisplayName' => 'test'],
+				['getDisplayName' => 'test', 'getMentionPermissions' => 0],
 				['getAttendee' => Attendee::fromRow([
 					'actor_type' => Attendee::ACTOR_GUESTS,
 					'actor_id' => 'guest',
 				])],
 				[['id' => 'all', 'label' => 'test', 'source' => 'calls', 'mentionId' => 'all']]
-			]
+			],
 		];
 	}
 
 	/**
 	 * @dataProvider dataAddConversationNotify
 	 */
-	public function testAddConversationNotify(string $search, array$roomMocks, array $participantMocks, array $expected): void {
+	public function testAddConversationNotify(string $search, array $roomMocks, array $participantMocks, array $expected): void {
 		$room = $this->createMock(Room::class);
 		foreach ($roomMocks as $method => $return) {
 			$room->expects($this->once())
diff --git a/tests/php/Chat/NotifierTest.php b/tests/php/Chat/NotifierTest.php
index 72b84d75479..445b56b51c7 100644
--- a/tests/php/Chat/NotifierTest.php
+++ b/tests/php/Chat/NotifierTest.php
@@ -176,7 +176,8 @@ public function testNotifyMentionedUsers(string $message, array $alreadyNotified
 		$room = $this->getRoom();
 		$comment = $this->newComment('108', 'users', 'testUser', new \DateTime('@' . 1000000016), $message);
 		$notifier = $this->getNotifier([]);
-		$actual = $notifier->notifyMentionedUsers($room, $comment, $alreadyNotifiedUsers, false);
+		$participant = $this->createMock(Participant::class);
+		$actual = $notifier->notifyMentionedUsers($room, $comment, $alreadyNotifiedUsers, false, $participant);
 
 		$this->assertEqualsCanonicalizing($expectedReturn, $actual);
 	}
@@ -286,6 +287,8 @@ public static function dataAddMentionAllToList(): array {
 			'not notify' => [
 				[],
 				[],
+				0,
+				true,
 				[],
 			],
 			'preserve notify list and do not notify all' => [
@@ -293,6 +296,8 @@ public static function dataAddMentionAllToList(): array {
 					['id' => 'user1', 'type' => Attendee::ACTOR_USERS, 'reason' => 'direct'],
 				],
 				[],
+				0,
+				true,
 				[
 					['id' => 'user1', 'type' => Attendee::ACTOR_USERS, 'reason' => 'direct'],
 				],
@@ -306,24 +311,48 @@ public static function dataAddMentionAllToList(): array {
 					Attendee::fromRow(['actor_id' => 'user1', 'actor_type' => Attendee::ACTOR_USERS]),
 					Attendee::fromRow(['actor_id' => 'user2', 'actor_type' => Attendee::ACTOR_USERS]),
 				],
+				0,
+				false,
 				[
 					['id' => 'user1', 'type' => Attendee::ACTOR_USERS, 'reason' => 'direct'],
 					['id' => 'user2', 'type' => Attendee::ACTOR_USERS, 'reason' => 'all'],
 				],
 			],
+			'prevent non-moderator to notify all' => [
+				[
+					['id' => 'user1', 'type' => Attendee::ACTOR_USERS, 'reason' => 'direct'],
+					['id' => 'all', 'type' => Attendee::ACTOR_USERS, 'reason' => 'direct'],
+				],
+				[
+					Attendee::fromRow(['actor_id' => 'user1', 'actor_type' => Attendee::ACTOR_USERS]),
+					Attendee::fromRow(['actor_id' => 'user2', 'actor_type' => Attendee::ACTOR_USERS]),
+				],
+				1,
+				false,
+				[
+					['id' => 'user1', 'type' => Attendee::ACTOR_USERS, 'reason' => 'direct'],
+				],
+			],
 		];
 	}
 
 	/**
 	 * @dataProvider dataAddMentionAllToList
 	 */
-	public function testAddMentionAllToList(array $usersToNotify, array $participants, array $return): void {
+	public function testAddMentionAllToList(array $usersToNotify, array $participants, int $mentionPermissions, bool $moderatorPermissions, array $return): void {
 		$room = $this->createMock(Room::class);
+		$room->method('getMentionPermissions')
+			->willReturn($mentionPermissions);
+
 		$this->participantService
 			->method('getActorsByType')
 			->willReturn($participants);
 
-		$actual = self::invokePrivate($this->getNotifier(), 'addMentionAllToList', [$room, $usersToNotify]);
+		$participant = $this->createMock(Participant::class);
+		$participant->method('hasModeratorPermissions')
+			->willReturn($moderatorPermissions);
+
+		$actual = self::invokePrivate($this->getNotifier(), 'addMentionAllToList', [$room, $usersToNotify, $participant]);
 		$this->assertCount(count($return), $actual);
 		foreach ($actual as $key => $value) {
 			$this->assertIsArray($value);
diff --git a/tests/php/Chat/Parser/UserMentionTest.php b/tests/php/Chat/Parser/UserMentionTest.php
index 60e9aac9713..5f9386ce6e0 100644
--- a/tests/php/Chat/Parser/UserMentionTest.php
+++ b/tests/php/Chat/Parser/UserMentionTest.php
@@ -65,13 +65,18 @@ public function setUp(): void {
 
 	/**
 	 * @param array $mentions
+	 * @param array|null $metadata
 	 * @return MockObject|IComment
 	 */
-	private function newComment(array $mentions): IComment {
+	private function newComment(array $mentions, ?array $metadata = null): IComment {
 		$comment = $this->createMock(IComment::class);
 
 		$comment->method('getMentions')->willReturn($mentions);
 
+		if ($metadata !== null) {
+			$comment->method('getMetaData')->willReturn($metadata);
+		}
+
 		return $comment;
 	}
 
@@ -385,7 +390,10 @@ public function testGetRichMessageWithAtAll(): void {
 		$mentions = [
 			['type' => 'user', 'id' => 'all'],
 		];
-		$comment = $this->newComment($mentions);
+		$metadata = [
+			Message::METADATA_CAN_MENTION_ALL => true,
+		];
+		$comment = $this->newComment($mentions, $metadata);
 
 		/** @var Room&MockObject $room */
 		$room = $this->createMock(Room::class);
diff --git a/tests/php/Service/RoomServiceTest.php b/tests/php/Service/RoomServiceTest.php
index b43ecc21a19..7307630cef9 100644
--- a/tests/php/Service/RoomServiceTest.php
+++ b/tests/php/Service/RoomServiceTest.php
@@ -366,6 +366,7 @@ public function testVerifyPassword(): void {
 			Room::RECORDING_NONE,
 			RecordingService::CONSENT_REQUIRED_NO,
 			Room::HAS_FEDERATION_NONE,
+			Room::MENTION_PERMISSIONS_EVERYONE,
 		);
 
 		$verificationResult = $service->verifyPassword($room, '1234');