diff --git a/appinfo/info.xml b/appinfo/info.xml
index c5034914a5c..ce22dac5020 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>24.0.0-dev.2</version>
+	<version>24.0.0-dev.3</version>
 	<licence>agpl</licence>
 
 	<author>Anna Larch</author>
diff --git a/docs/capabilities.md b/docs/capabilities.md
index 58f2ea9d908..6d1a1f0d3e8 100644
--- a/docs/capabilities.md
+++ b/docs/capabilities.md
@@ -226,3 +226,4 @@
 * `config => conversations => group-mode` (local) - User selected grouping mode for conversations (`none`, `group-first` or `private-first`)
 * `private-reply` - Whether clients can link the original message to a private reply in one-to-one conversations
 * `config => attachments => conversation-subfolders` (local) - Whether per-conversation subfolders are used for Talk attachments; when `true` files must be uploaded to `Talk/<ConversationName>-<token>/<DisplayName>-<uid>/` before calling the attachment endpoint
+* `mute-conversations` - Whether conversations can be muted for a given time
diff --git a/lib/Capabilities.php b/lib/Capabilities.php
index db47841106c..8856d7f2274 100644
--- a/lib/Capabilities.php
+++ b/lib/Capabilities.php
@@ -132,6 +132,7 @@ class Capabilities implements IPublicCapability {
 		'scheduled-messages',
 		'conversation-presets',
 		'private-reply',
+		'mute-conversations',
 	];
 
 	public const CONDITIONAL_FEATURES = [
diff --git a/lib/Chat/Notifier.php b/lib/Chat/Notifier.php
index 30f35f3b93c..a1fb24952a8 100644
--- a/lib/Chat/Notifier.php
+++ b/lib/Chat/Notifier.php
@@ -692,6 +692,10 @@ protected function shouldMentionedUserBeNotified(string $userId, IComment $comme
 				return self::PRIORITY_NONE;
 			}
 
+			if ($attendee->getMuteUntil() >= $this->timeFactory->getTime()) {
+				return self::PRIORITY_NONE;
+			}
+
 			$notificationLevel = $attendee->getNotificationLevel();
 			$threadId = (int)$comment->getTopmostParentId();
 			if ($threadId !== 0) {
@@ -768,6 +772,10 @@ protected function shouldParticipantBeNotified(Participant $participant, ICommen
 			return self::PRIORITY_NONE;
 		}
 
+		if ($participant->getAttendee()->getMuteUntil() >= $this->timeFactory->getTime()) {
+			return self::PRIORITY_NONE;
+		}
+
 		if ($participant->getAttendee()->isImportant()) {
 			return self::PRIORITY_IMPORTANT;
 		}
diff --git a/lib/Controller/RoomController.php b/lib/Controller/RoomController.php
index 1e1e9ca838d..3c32552239f 100644
--- a/lib/Controller/RoomController.php
+++ b/lib/Controller/RoomController.php
@@ -3238,4 +3238,54 @@ public function scheduleMeeting(string $calendarUri, int $start, ?array $attende
 
 		return new DataResponse(null, Http::STATUS_OK);
 	}
+
+	/**
+	 * Mute all notifications in a conversation until a specific time.
+	 * Does not alter notification settings for the attendee.
+	 *
+	 * Required capability: `mute-conversations`
+	 *
+	 * @param int $muteUntil Unix timestamp until notifications are muted
+	 * @return DataResponse<Http::STATUS_OK, TalkRoom, array{}>|DataResponse<Http::STATUS_BAD_REQUEST, array{error: 'mute-until'}, array{}>
+	 *
+	 * 200: Conversation muted
+	 * 400: Timestamp is in the past
+	 */
+	#[NoAdminRequired]
+	#[FederationSupported]
+	#[RequireLoggedInParticipant]
+	#[ApiRoute(verb: 'POST', url: '/api/{apiVersion}/room/{token}/mute', requirements: [
+		'apiVersion' => '(v4)',
+		'token' => '[a-z0-9]{4,30}',
+	])]
+	public function muteConversation(int $muteUntil): DataResponse {
+		if ($muteUntil <= $this->timeFactory->getTime()) {
+			return new DataResponse(['error' => 'mute-until'], Http::STATUS_BAD_REQUEST);
+		}
+
+		$this->participantService->setMuteUntil($this->participant, $muteUntil);
+		return new DataResponse($this->formatRoom($this->room, $this->participant));
+	}
+
+	/**
+	 * Unmute all notifications in a conversation, when they were muted before.
+	 * Does not alter notification settings for the attendee.
+	 *
+	 * Required capability: `mute-conversations`
+	 *
+	 * @return DataResponse<Http::STATUS_OK, TalkRoom, array{}>
+	 *
+	 * 200: Conversation unmuted
+	 */
+	#[NoAdminRequired]
+	#[FederationSupported]
+	#[RequireLoggedInParticipant]
+	#[ApiRoute(verb: 'DELETE', url: '/api/{apiVersion}/room/{token}/mute', requirements: [
+		'apiVersion' => '(v4)',
+		'token' => '[a-z0-9]{4,30}',
+	])]
+	public function unmuteConversation(): DataResponse {
+		$this->participantService->setMuteUntil($this->participant, 0);
+		return new DataResponse($this->formatRoom($this->room, $this->participant));
+	}
 }
diff --git a/lib/Migration/Version24000Date20260419190830.php b/lib/Migration/Version24000Date20260419190830.php
new file mode 100644
index 00000000000..2feae38211a
--- /dev/null
+++ b/lib/Migration/Version24000Date20260419190830.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 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;
+use Override;
+
+class Version24000Date20260419190830 extends SimpleMigrationStep {
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure(): ISchemaWrapper $schemaClosure
+	 * @param array $options
+	 * @return null|ISchemaWrapper
+	 */
+	#[Override]
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$table = $schema->getTable('talk_attendees');
+		if (!$table->hasColumn('mute_until')) {
+			$table->addColumn('mute_until', Types::BIGINT, [
+				'notnull' => true,
+				'default' => 0,
+			]);
+		}
+
+		return $schema;
+	}
+}
diff --git a/lib/Model/Attendee.php b/lib/Model/Attendee.php
index 75cb0013f72..c56c8185efb 100644
--- a/lib/Model/Attendee.php
+++ b/lib/Model/Attendee.php
@@ -74,6 +74,8 @@
  * @method int getHiddenPinnedId()
  * @method void setHasScheduledMessages(int $scheduledMessages)
  * @method int getHasScheduledMessages()
+ * @method void setMuteUntil(int $muteUntil)
+ * @method int getMuteUntil()
  */
 class Attendee extends Entity {
 	public const ACTOR_USERS = 'users';
@@ -150,6 +152,7 @@ class Attendee extends Entity {
 	protected bool $hasUnreadThreadDirects = false;
 	protected int $hiddenPinnedId = 0;
 	protected int $hasScheduledMessages = 0;
+	protected int $muteUntil = 0;
 
 	public function __construct() {
 		$this->addType('roomId', Types::BIGINT);
@@ -183,7 +186,7 @@ public function __construct() {
 		$this->addType('hasUnreadThreadDirects', Types::BOOLEAN);
 		$this->addType('hiddenPinnedId', Types::BIGINT);
 		$this->addType('hasScheduledMessages', Types::INTEGER);
-
+		$this->addType('muteUntil', Types::BIGINT);
 	}
 
 	public function getDisplayName(): string {
diff --git a/lib/Model/AttendeeMapper.php b/lib/Model/AttendeeMapper.php
index f1715b06d1e..fd6aebaa1c0 100644
--- a/lib/Model/AttendeeMapper.php
+++ b/lib/Model/AttendeeMapper.php
@@ -316,6 +316,7 @@ public function createAttendeeFromRow(array $row): Attendee {
 			'has_unread_thread_directs' => (bool)$row['has_unread_thread_directs'],
 			'hidden_pinned_id' => (int)$row['hidden_pinned_id'],
 			'has_scheduled_messages' => (int)$row['has_scheduled_messages'],
+			'mute_until' => (int)$row['mute_until'],
 		]);
 	}
 }
diff --git a/lib/Model/SelectHelper.php b/lib/Model/SelectHelper.php
index 6ccc084f84f..9be81cc9a4e 100644
--- a/lib/Model/SelectHelper.php
+++ b/lib/Model/SelectHelper.php
@@ -114,6 +114,7 @@ public function selectAttendeesTable(IQueryBuilder $query, string $alias = 'a'):
 			$alias . 'has_unread_thread_directs',
 			$alias . 'hidden_pinned_id',
 			$alias . 'has_scheduled_messages',
+			$alias . 'mute_until',
 		])->selectAlias($alias . 'id', 'a_id');
 	}
 
diff --git a/lib/ResponseDefinitions.php b/lib/ResponseDefinitions.php
index 6f1a8e00aec..041f380071c 100644
--- a/lib/ResponseDefinitions.php
+++ b/lib/ResponseDefinitions.php
@@ -570,6 +570,8 @@
  *     hasScheduledMessages: int,
  *     // Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details
  *     attributes: int,
+ *     // Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications
+ *     muteUntil: int,
  * }
  *
  * @psalm-type TalkDashboardEventAttachment = array{
diff --git a/lib/Service/ParticipantService.php b/lib/Service/ParticipantService.php
index b0dc6c87f10..dfd03443b39 100644
--- a/lib/Service/ParticipantService.php
+++ b/lib/Service/ParticipantService.php
@@ -382,6 +382,13 @@ public function hidePinnedMessage(Participant $participant, int $messagesId): vo
 		$this->attendeeMapper->update($attendee);
 	}
 
+	public function setMuteUntil(Participant $participant, int $muteUntil): void {
+		$attendee = $participant->getAttendee();
+		$attendee->setMuteUntil($muteUntil);
+		$attendee->setLastAttendeeActivity($this->timeFactory->getTime());
+		$this->attendeeMapper->update($attendee);
+	}
+
 	/**
 	 * @param RoomService $roomService
 	 * @param Room $room
@@ -2058,6 +2065,7 @@ public function getParticipantUsersForCallNotifications(Room $room): array {
 			->where($query->expr()->eq('a.room_id', $query->createNamedParameter($room->getId(), IQueryBuilder::PARAM_INT)))
 			->andWhere($query->expr()->eq('a.actor_type', $query->createNamedParameter(Attendee::ACTOR_USERS)))
 			->andWhere($query->expr()->eq('a.notification_calls', $query->createNamedParameter(Participant::NOTIFY_CALLS_ON)))
+			->andWhere($query->expr()->lte('a.mute_until', $query->createNamedParameter($this->timeFactory->getTime(), IQueryBuilder::PARAM_INT)))
 			->andWhere($query->expr()->isNull('s.in_call'));
 
 		if ($room->getLobbyState() !== Webinary::LOBBY_NONE) {
diff --git a/lib/Service/RoomFormatter.php b/lib/Service/RoomFormatter.php
index 2af9f20aa0e..92f875d7260 100644
--- a/lib/Service/RoomFormatter.php
+++ b/lib/Service/RoomFormatter.php
@@ -160,6 +160,7 @@ public function formatRoomV4(
 			'isSensitive' => false,
 			'hasScheduledMessages' => 0,
 			'attributes' => 0,
+			'muteUntil' => 0,
 		];
 
 		if ($room->isFederatedConversation()) {
@@ -251,6 +252,7 @@ public function formatRoomV4(
 			'lastPinnedId' => $room->getLastPinnedId(),
 			'hiddenPinnedId' => $attendee->getHiddenPinnedId(),
 			'attributes' => $room->getAttributes(),
+			'muteUntil' => $attendee->getMuteUntil(),
 		]);
 
 		if ($room->isFederatedConversation()) {
diff --git a/openapi-backend-sipbridge.json b/openapi-backend-sipbridge.json
index c23432e87eb..50628184c0c 100644
--- a/openapi-backend-sipbridge.json
+++ b/openapi-backend-sipbridge.json
@@ -941,7 +941,8 @@
                     "lastPinnedId",
                     "hiddenPinnedId",
                     "hasScheduledMessages",
-                    "attributes"
+                    "attributes",
+                    "muteUntil"
                 ],
                 "properties": {
                     "actorId": {
@@ -1255,6 +1256,11 @@
                         "type": "integer",
                         "format": "int64",
                         "description": "Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details"
+                    },
+                    "muteUntil": {
+                        "type": "integer",
+                        "format": "int64",
+                        "description": "Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications"
                     }
                 }
             },
diff --git a/openapi-federation.json b/openapi-federation.json
index 1f99fd6b5da..377569a4136 100644
--- a/openapi-federation.json
+++ b/openapi-federation.json
@@ -1006,7 +1006,8 @@
                     "lastPinnedId",
                     "hiddenPinnedId",
                     "hasScheduledMessages",
-                    "attributes"
+                    "attributes",
+                    "muteUntil"
                 ],
                 "properties": {
                     "actorId": {
@@ -1320,6 +1321,11 @@
                         "type": "integer",
                         "format": "int64",
                         "description": "Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details"
+                    },
+                    "muteUntil": {
+                        "type": "integer",
+                        "format": "int64",
+                        "description": "Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications"
                     }
                 }
             },
diff --git a/openapi-full.json b/openapi-full.json
index cd620ec092c..4f6e233b8f6 100644
--- a/openapi-full.json
+++ b/openapi-full.json
@@ -1990,7 +1990,8 @@
                     "lastPinnedId",
                     "hiddenPinnedId",
                     "hasScheduledMessages",
-                    "attributes"
+                    "attributes",
+                    "muteUntil"
                 ],
                 "properties": {
                     "actorId": {
@@ -2304,6 +2305,11 @@
                         "type": "integer",
                         "format": "int64",
                         "description": "Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details"
+                    },
+                    "muteUntil": {
+                        "type": "integer",
+                        "format": "int64",
+                        "description": "Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications"
                     }
                 }
             },
@@ -25587,6 +25593,287 @@
                 }
             }
         },
+        "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mute": {
+            "post": {
+                "operationId": "room-mute-conversation",
+                "summary": "Mute all notifications in a conversation until a specific time. Does not alter notification settings for the attendee.",
+                "description": "Required capability: `mute-conversations`",
+                "tags": [
+                    "room"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "requestBody": {
+                    "required": true,
+                    "content": {
+                        "application/json": {
+                            "schema": {
+                                "type": "object",
+                                "required": [
+                                    "muteUntil"
+                                ],
+                                "properties": {
+                                    "muteUntil": {
+                                        "type": "integer",
+                                        "format": "int64",
+                                        "description": "Unix timestamp until notifications are muted"
+                                    }
+                                }
+                            }
+                        }
+                    }
+                },
+                "parameters": [
+                    {
+                        "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": "Conversation muted",
+                        "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": "Timestamp is in the past",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {
+                                                    "type": "object",
+                                                    "required": [
+                                                        "error"
+                                                    ],
+                                                    "properties": {
+                                                        "error": {
+                                                            "type": "string",
+                                                            "enum": [
+                                                                "mute-until"
+                                                            ]
+                                                        }
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "401": {
+                        "description": "Current user is not logged in",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            },
+            "delete": {
+                "operationId": "room-unmute-conversation",
+                "summary": "Unmute all notifications in a conversation, when they were muted before. Does not alter notification settings for the attendee.",
+                "description": "Required capability: `mute-conversations`",
+                "tags": [
+                    "room"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "parameters": [
+                    {
+                        "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}$"
+                        }
+                    },
+                    {
+                        "name": "OCS-APIRequest",
+                        "in": "header",
+                        "description": "Required to be true for the API request to pass",
+                        "required": true,
+                        "schema": {
+                            "type": "boolean",
+                            "default": true
+                        }
+                    }
+                ],
+                "responses": {
+                    "200": {
+                        "description": "Conversation unmuted",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {
+                                                    "$ref": "#/components/schemas/Room"
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "401": {
+                        "description": "Current user is not logged in",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$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 d80abd78355..e8898b71b0f 100644
--- a/openapi.json
+++ b/openapi.json
@@ -1878,7 +1878,8 @@
                     "lastPinnedId",
                     "hiddenPinnedId",
                     "hasScheduledMessages",
-                    "attributes"
+                    "attributes",
+                    "muteUntil"
                 ],
                 "properties": {
                     "actorId": {
@@ -2192,6 +2193,11 @@
                         "type": "integer",
                         "format": "int64",
                         "description": "Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details"
+                    },
+                    "muteUntil": {
+                        "type": "integer",
+                        "format": "int64",
+                        "description": "Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications"
                     }
                 }
             },
@@ -25475,6 +25481,287 @@
                 }
             }
         },
+        "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mute": {
+            "post": {
+                "operationId": "room-mute-conversation",
+                "summary": "Mute all notifications in a conversation until a specific time. Does not alter notification settings for the attendee.",
+                "description": "Required capability: `mute-conversations`",
+                "tags": [
+                    "room"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "requestBody": {
+                    "required": true,
+                    "content": {
+                        "application/json": {
+                            "schema": {
+                                "type": "object",
+                                "required": [
+                                    "muteUntil"
+                                ],
+                                "properties": {
+                                    "muteUntil": {
+                                        "type": "integer",
+                                        "format": "int64",
+                                        "description": "Unix timestamp until notifications are muted"
+                                    }
+                                }
+                            }
+                        }
+                    }
+                },
+                "parameters": [
+                    {
+                        "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}$"
+                        }
+                    },
+                    {
+                        "name": "OCS-APIRequest",
+                        "in": "header",
+                        "description": "Required to be true for the API request to pass",
+                        "required": true,
+                        "schema": {
+                            "type": "boolean",
+                            "default": true
+                        }
+                    }
+                ],
+                "responses": {
+                    "200": {
+                        "description": "Conversation muted",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {
+                                                    "$ref": "#/components/schemas/Room"
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "400": {
+                        "description": "Timestamp is in the past",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {
+                                                    "type": "object",
+                                                    "required": [
+                                                        "error"
+                                                    ],
+                                                    "properties": {
+                                                        "error": {
+                                                            "type": "string",
+                                                            "enum": [
+                                                                "mute-until"
+                                                            ]
+                                                        }
+                                                    }
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "401": {
+                        "description": "Current user is not logged in",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "required": [
+                                        "ocs"
+                                    ],
+                                    "properties": {
+                                        "ocs": {
+                                            "type": "object",
+                                            "required": [
+                                                "meta",
+                                                "data"
+                                            ],
+                                            "properties": {
+                                                "meta": {
+                                                    "$ref": "#/components/schemas/OCSMeta"
+                                                },
+                                                "data": {}
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            },
+            "delete": {
+                "operationId": "room-unmute-conversation",
+                "summary": "Unmute all notifications in a conversation, when they were muted before. Does not alter notification settings for the attendee.",
+                "description": "Required capability: `mute-conversations`",
+                "tags": [
+                    "room"
+                ],
+                "security": [
+                    {
+                        "bearer_auth": []
+                    },
+                    {
+                        "basic_auth": []
+                    }
+                ],
+                "parameters": [
+                    {
+                        "name": "apiVersion",
+                        "in": "path",
+                        "required": true,
+                        "schema": {
+                            "type": "string",
+                            "enum": [
+                                "v4"
+                            ],
+                            "default": "v4"
+                        }
+                    },
+                    {
+                        "name": "token",
+                        "in": "path",
+                        "required": true,
+                        "schema": {
+                            "type": "string",
+                            "pattern": "^[a-z0-9]{4,30}$"
+                        }
+                    },
+                    {
+                        "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": "Conversation unmuted",
+                        "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"
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    },
+                    "401": {
+                        "description": "Current user is not logged in",
+                        "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/types/openapi/openapi-backend-sipbridge.ts b/src/types/openapi/openapi-backend-sipbridge.ts
index 4fa17d36ce1..6f203a17002 100644
--- a/src/types/openapi/openapi-backend-sipbridge.ts
+++ b/src/types/openapi/openapi-backend-sipbridge.ts
@@ -782,6 +782,11 @@ export type components = {
              * @description Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details
              */
             attributes: number;
+            /**
+             * Format: int64
+             * @description Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications
+             */
+            muteUntil: number;
         };
         RoomLastMessage: components["schemas"]["ChatMessage"] | components["schemas"]["ChatProxyMessage"];
     };
diff --git a/src/types/openapi/openapi-federation.ts b/src/types/openapi/openapi-federation.ts
index 7160990adda..ed6246bae83 100644
--- a/src/types/openapi/openapi-federation.ts
+++ b/src/types/openapi/openapi-federation.ts
@@ -826,6 +826,11 @@ export type components = {
              * @description Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details
              */
             attributes: number;
+            /**
+             * Format: int64
+             * @description Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications
+             */
+            muteUntil: number;
         };
         RoomLastMessage: components["schemas"]["ChatMessage"] | components["schemas"]["ChatProxyMessage"];
     };
diff --git a/src/types/openapi/openapi-full.ts b/src/types/openapi/openapi-full.ts
index d2ba011e53d..359f4fd8106 100644
--- a/src/types/openapi/openapi-full.ts
+++ b/src/types/openapi/openapi-full.ts
@@ -1782,6 +1782,30 @@ export type paths = {
         patch?: never;
         trace?: never;
     };
+    "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mute": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        /**
+         * Mute all notifications in a conversation until a specific time. Does not alter notification settings for the attendee.
+         * @description Required capability: `mute-conversations`
+         */
+        post: operations["room-mute-conversation"];
+        /**
+         * Unmute all notifications in a conversation, when they were muted before. Does not alter notification settings for the attendee.
+         * @description Required capability: `mute-conversations`
+         */
+        delete: operations["room-unmute-conversation"];
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/ocs/v2.php/apps/spreed/api/{apiVersion}/settings/user": {
         parameters: {
             query?: never;
@@ -3581,6 +3605,11 @@ export type components = {
              * @description Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details
              */
             attributes: number;
+            /**
+             * Format: int64
+             * @description Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications
+             */
+            muteUntil: number;
         };
         RoomLastMessage: components["schemas"]["ChatMessage"] | components["schemas"]["ChatProxyMessage"];
         RoomWithInvalidInvitations: components["schemas"]["Room"] & {
@@ -12933,6 +12962,123 @@ export interface operations {
             };
         };
     };
+    "room-mute-conversation": {
+        parameters: {
+            query?: never;
+            header: {
+                /** @description Required to be true for the API request to pass */
+                "OCS-APIRequest": boolean;
+            };
+            path: {
+                apiVersion: "v4";
+                token: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": {
+                    /**
+                     * Format: int64
+                     * @description Unix timestamp until notifications are muted
+                     */
+                    muteUntil: number;
+                };
+            };
+        };
+        responses: {
+            /** @description Conversation muted */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: components["schemas"]["Room"];
+                        };
+                    };
+                };
+            };
+            /** @description Timestamp is in the past */
+            400: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: {
+                                /** @enum {string} */
+                                error: "mute-until";
+                            };
+                        };
+                    };
+                };
+            };
+            /** @description Current user is not logged in */
+            401: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: unknown;
+                        };
+                    };
+                };
+            };
+        };
+    };
+    "room-unmute-conversation": {
+        parameters: {
+            query?: never;
+            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 Conversation unmuted */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: components["schemas"]["Room"];
+                        };
+                    };
+                };
+            };
+            /** @description Current user is not logged in */
+            401: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: unknown;
+                        };
+                    };
+                };
+            };
+        };
+    };
     "settings-set-user-setting": {
         parameters: {
             query?: never;
diff --git a/src/types/openapi/openapi.ts b/src/types/openapi/openapi.ts
index 38444c0a210..16324f78962 100644
--- a/src/types/openapi/openapi.ts
+++ b/src/types/openapi/openapi.ts
@@ -1782,6 +1782,30 @@ export type paths = {
         patch?: never;
         trace?: never;
     };
+    "/ocs/v2.php/apps/spreed/api/{apiVersion}/room/{token}/mute": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        get?: never;
+        put?: never;
+        /**
+         * Mute all notifications in a conversation until a specific time. Does not alter notification settings for the attendee.
+         * @description Required capability: `mute-conversations`
+         */
+        post: operations["room-mute-conversation"];
+        /**
+         * Unmute all notifications in a conversation, when they were muted before. Does not alter notification settings for the attendee.
+         * @description Required capability: `mute-conversations`
+         */
+        delete: operations["room-unmute-conversation"];
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/ocs/v2.php/apps/spreed/api/{apiVersion}/settings/user": {
         parameters: {
             query?: never;
@@ -3014,6 +3038,11 @@ export type components = {
              * @description Bit-flag of enabled attributes of this conversation (only available with capability: `conversation-attributes`). See [attributes list](https://nextcloud-talk.readthedocs.io/en/latest/constants/#conversation-attributes) for details
              */
             attributes: number;
+            /**
+             * Format: int64
+             * @description Required capability: `mute-conversations`. Timestamp until the conversation is muted, i.e. not receiving notifications
+             */
+            muteUntil: number;
         };
         RoomLastMessage: components["schemas"]["ChatMessage"] | components["schemas"]["ChatProxyMessage"];
         RoomWithInvalidInvitations: components["schemas"]["Room"] & {
@@ -12366,6 +12395,123 @@ export interface operations {
             };
         };
     };
+    "room-mute-conversation": {
+        parameters: {
+            query?: never;
+            header: {
+                /** @description Required to be true for the API request to pass */
+                "OCS-APIRequest": boolean;
+            };
+            path: {
+                apiVersion: "v4";
+                token: string;
+            };
+            cookie?: never;
+        };
+        requestBody: {
+            content: {
+                "application/json": {
+                    /**
+                     * Format: int64
+                     * @description Unix timestamp until notifications are muted
+                     */
+                    muteUntil: number;
+                };
+            };
+        };
+        responses: {
+            /** @description Conversation muted */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: components["schemas"]["Room"];
+                        };
+                    };
+                };
+            };
+            /** @description Timestamp is in the past */
+            400: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: {
+                                /** @enum {string} */
+                                error: "mute-until";
+                            };
+                        };
+                    };
+                };
+            };
+            /** @description Current user is not logged in */
+            401: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: unknown;
+                        };
+                    };
+                };
+            };
+        };
+    };
+    "room-unmute-conversation": {
+        parameters: {
+            query?: never;
+            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 Conversation unmuted */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: components["schemas"]["Room"];
+                        };
+                    };
+                };
+            };
+            /** @description Current user is not logged in */
+            401: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": {
+                        ocs: {
+                            meta: components["schemas"]["OCSMeta"];
+                            data: unknown;
+                        };
+                    };
+                };
+            };
+        };
+    };
     "settings-set-user-setting": {
         parameters: {
             query?: never;
diff --git a/tests/integration/features/bootstrap/FeatureContext.php b/tests/integration/features/bootstrap/FeatureContext.php
index f8e1f212d97..4f2eb79c29d 100644
--- a/tests/integration/features/bootstrap/FeatureContext.php
+++ b/tests/integration/features/bootstrap/FeatureContext.php
@@ -548,6 +548,12 @@ private function assertRooms(array $rooms, TableNode $formData, bool $shouldOrde
 						$data['lobbyTimer'] = 'GREATER_THAN_ZERO';
 					}
 				}
+				if (isset($expectedRoom['muteUntil'])) {
+					$data['muteUntil'] = (int)$room['muteUntil'];
+					if ($expectedRoom['muteUntil'] === 'GREATER_THAN_ZERO' && $room['muteUntil'] > 0) {
+						$data['muteUntil'] = 'GREATER_THAN_ZERO';
+					}
+				}
 				if (isset($expectedRoom['breakoutRoomMode'])) {
 					$data['breakoutRoomMode'] = (int)$room['breakoutRoomMode'];
 				}
@@ -4975,6 +4981,26 @@ public function userMarksConversationSensitive(string $user, string $identifier,
 		$this->assertStatusCode($this->response, $statusCode);
 	}
 
+	#[When('/^user "([^"]*)" mutes room "([^"]*)" until OFFSET\((\d+)\) with (\d+) \((v4)\)$/')]
+	public function userMutesConversationUntil(string $user, string $identifier, int $muteUntil, int $statusCode, string $apiVersion): void {
+		$this->setCurrentUser($user);
+		$this->sendRequest(
+			'POST', '/apps/spreed/api/' . $apiVersion . '/room/' . self::$identifierToToken[$identifier] . '/mute', [
+				'muteUntil' => time() + $muteUntil,
+			],
+		);
+		$this->assertStatusCode($this->response, $statusCode);
+	}
+
+	#[When('/^user "([^"]*)" unmutes room "([^"]*)" with (\d+) \((v4)\)$/')]
+	public function userUnmutesConversationUntil(string $user, string $identifier, int $statusCode, string $apiVersion): void {
+		$this->setCurrentUser($user);
+		$this->sendRequest(
+			'DELETE', '/apps/spreed/api/' . $apiVersion . '/room/' . self::$identifierToToken[$identifier] . '/mute',
+		);
+		$this->assertStatusCode($this->response, $statusCode);
+	}
+
 	public function sendRequestFullUrl(string $verb, string $fullUrl, TableNode|array|string|null $body = null, array $headers = [], array $options = []): void {
 		$client = new Client();
 		$options = array_merge($options, ['cookies' => $this->getUserCookieJar($this->currentUser)]);
diff --git a/tests/integration/features/conversation-5/mute.feature b/tests/integration/features/conversation-5/mute.feature
new file mode 100644
index 00000000000..1bffbf0da2c
--- /dev/null
+++ b/tests/integration/features/conversation-5/mute.feature
@@ -0,0 +1,50 @@
+Feature: conversation-5/mute
+  Background:
+    Given user "participant1" exists
+    Given user "participant2" exists
+
+  Scenario: Mark as (un-)mute
+    Given user "participant1" creates room "group room" (v4)
+      | roomType | 3 |
+      | roomName | room |
+    And user "participant1" is participant of the following unordered rooms (v4)
+      | id              | name         | muteUntil |
+      | group room      | room         | 0         |
+    And user "participant1" mutes room "group room" until OFFSET(3600) with 200 (v4)
+    And user "participant1" is participant of the following unordered rooms (v4)
+      | id              | name         | muteUntil         |
+      | group room      | room         | GREATER_THAN_ZERO |
+    And user "participant1" unmutes room "group room" with 200 (v4)
+    And user "participant1" is participant of the following unordered rooms (v4)
+      | id              | name         | muteUntil |
+      | group room      | room         | 0         |
+
+  Scenario: No notifications for muted rooms
+    When user "participant1" creates room "one-to-one room" (v4)
+      | roomType | 1 |
+      | invite   | participant2 |
+    And user "participant2" creates room "one-to-one room" with 200 (v4)
+      | roomType | 1 |
+      | invite   | participant1 |
+    And user "participant1" sends message "Message1" to room "one-to-one room" with 201
+    And user "participant2" mutes room "one-to-one room" until OFFSET(3600) with 200 (v4)
+    And user "participant1" sends message "Message with mention for @participant2" to room "one-to-one room" with 201
+    Then user "participant2" has the following notifications
+      | app    | object_type | object_id                | subject                                              | message  |
+      | spreed | chat        | one-to-one room/Message1 | participant1-displayname sent you a private message  | Message1 |
+    And user "participant2" unmutes room "one-to-one room" with 200 (v4)
+    Then user "participant2" has the following notifications
+      | app    | object_type | object_id                | subject                                              | message  |
+      | spreed | chat        | one-to-one room/Message1 | participant1-displayname sent you a private message  | Message1 |
+
+  Scenario: Participant1 calls while participant2 has muted the conversation
+    When user "participant1" creates room "room" (v4)
+      | roomType | 3 |
+      | roomName | room |
+    And user "participant1" adds user "participant2" to room "room" with 200 (v4)
+    Then user "participant1" is participant of room "room" (v4)
+    And user "participant2" is participant of room "room" (v4)
+    And user "participant2" mutes room "room" until OFFSET(3600) with 200 (v4)
+    Then user "participant1" joins room "room" with 200 (v4)
+    Then user "participant1" joins call "room" with 200 (v4)
+    Then user "participant2" has the following notifications
diff --git a/tests/php/Chat/ChatManagerTest.php b/tests/php/Chat/ChatManagerTest.php
index f931b8c27b2..2a9ef1680c3 100644
--- a/tests/php/Chat/ChatManagerTest.php
+++ b/tests/php/Chat/ChatManagerTest.php
@@ -444,6 +444,7 @@ public function testDeleteMessage(): void {
 			'has_unread_thread_directs' => false,
 			'hidden_pinned_id' => 0,
 			'has_scheduled_messages' => 0,
+			'mute_until' => 0,
 		]);
 		$chat = $this->createMock(Room::class);
 		$chat->expects($this->any())
@@ -514,6 +515,7 @@ public function testDeleteMessageFileShare(): void {
 			'has_unread_thread_directs' => false,
 			'hidden_pinned_id' => 0,
 			'has_scheduled_messages' => 0,
+			'mute_until' => 0,
 		]);
 		$chat = $this->createMock(Room::class);
 		$chat->expects($this->any())
@@ -606,6 +608,7 @@ public function testDeleteMessageFileShareNotFound(): void {
 			'has_unread_thread_directs' => false,
 			'hidden_pinned_id' => 0,
 			'has_scheduled_messages' => 0,
+			'mute_until' => 0,
 		]);
 		$chat = $this->createMock(Room::class);
 		$chat->expects($this->any())
diff --git a/tests/php/Chat/NotifierTest.php b/tests/php/Chat/NotifierTest.php
index eb0987342e8..6d7e079ddaf 100644
--- a/tests/php/Chat/NotifierTest.php
+++ b/tests/php/Chat/NotifierTest.php
@@ -177,6 +177,10 @@ public function testNotifyMentionedUsers(string $message, array $alreadyNotified
 				->method('notify');
 		}
 
+		$current = 1234567;
+		$this->timeFactory->method('getTime')
+			->willReturn($current);
+
 		$room = $this->getRoom();
 		$comment = $this->newComment('108', 'users', 'testUser', new \DateTime('@' . 1000000016), $message);
 		$notifier = $this->getNotifier([]);
@@ -188,24 +192,30 @@ public function testNotifyMentionedUsers(string $message, array $alreadyNotified
 
 	public static function dataShouldParticipantBeNotified(): array {
 		return [
-			[Attendee::ACTOR_GROUPS, 'test1', null, Attendee::ACTOR_USERS, 'test1', [], false, Notifier::PRIORITY_NONE],
-			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test1', [], false, Notifier::PRIORITY_NONE],
-			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [], false, Notifier::PRIORITY_NORMAL],
-			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [['id' => 'test1', 'type' => Attendee::ACTOR_USERS]], false, Notifier::PRIORITY_NONE],
-			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [['id' => 'test1', 'type' => Attendee::ACTOR_FEDERATED_USERS]], false, Notifier::PRIORITY_NORMAL],
-			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT - 5, Attendee::ACTOR_USERS, 'test2', [], false, Notifier::PRIORITY_NONE],
-			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT + 5, Attendee::ACTOR_USERS, 'test2', [], false, Notifier::PRIORITY_NORMAL],
+			[Attendee::ACTOR_GROUPS, 'test1', null, Attendee::ACTOR_USERS, 'test1', [], false, 0, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test1', [], false, 0, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [], false, 0, Notifier::PRIORITY_NORMAL],
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [['id' => 'test1', 'type' => Attendee::ACTOR_USERS]], false, 0, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [['id' => 'test1', 'type' => Attendee::ACTOR_FEDERATED_USERS]], false, 0, Notifier::PRIORITY_NORMAL],
+			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT - 5, Attendee::ACTOR_USERS, 'test2', [], false, 0, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT + 5, Attendee::ACTOR_USERS, 'test2', [], false, 0, Notifier::PRIORITY_NORMAL],
 
 			// Marked as important, still blocked by session and being the author, but otherwise with PRIORITY_IMPORTANT
-			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test1', [], true, Notifier::PRIORITY_NONE],
-			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [], true, Notifier::PRIORITY_IMPORTANT],
-			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT - 5, Attendee::ACTOR_USERS, 'test2', [], true, Notifier::PRIORITY_NONE],
-			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT + 5, Attendee::ACTOR_USERS, 'test2', [], true, Notifier::PRIORITY_IMPORTANT],
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test1', [], true, 0, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [], true, 0, Notifier::PRIORITY_IMPORTANT],
+			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT - 5, Attendee::ACTOR_USERS, 'test2', [], true, 0, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT + 5, Attendee::ACTOR_USERS, 'test2', [], true, 0, Notifier::PRIORITY_IMPORTANT],
+
+			// Marked as muted, no notification even with PRIORITY_IMPORTANT
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test1', [], true, 9999999, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', null, Attendee::ACTOR_USERS, 'test2', [], true, 9999999, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT - 5, Attendee::ACTOR_USERS, 'test2', [], true, 9999999, Notifier::PRIORITY_NONE],
+			[Attendee::ACTOR_USERS, 'test1', Session::SESSION_TIMEOUT + 5, Attendee::ACTOR_USERS, 'test2', [], true, 9999999, Notifier::PRIORITY_NONE],
 		];
 	}
 
 	#[DataProvider('dataShouldParticipantBeNotified')]
-	public function testShouldParticipantBeNotified(string $actorType, string $actorId, ?int $sessionAge, string $commentActorType, string $commentActorId, array $alreadyNotifiedUsers, bool $isImportant, int $expected): void {
+	public function testShouldParticipantBeNotified(string $actorType, string $actorId, ?int $sessionAge, string $commentActorType, string $commentActorId, array $alreadyNotifiedUsers, bool $isImportant, int $muteUntil, int $expected): void {
 		$comment = $this->createMock(IComment::class);
 		$comment->method('getActorType')
 			->willReturn($commentActorType);
@@ -217,13 +227,14 @@ public function testShouldParticipantBeNotified(string $actorType, string $actor
 			'actor_type' => $actorType,
 			'actor_id' => $actorId,
 			'important' => $isImportant,
+			'mute_until' => $muteUntil,
 		]);
+		$current = 1234567;
+		$this->timeFactory->method('getTime')
+			->willReturn($current);
+
 		$session = null;
 		if ($sessionAge !== null) {
-			$current = 1234567;
-			$this->timeFactory->method('getTime')
-				->willReturn($current);
-
 			$session = Session::fromRow([
 				'last_ping' => $current - $sessionAge,
 			]);