diff --git a/lib/Chat/Parser/SystemMessage.php b/lib/Chat/Parser/SystemMessage.php
index d6e2204c72e..558144f7ac2 100644
--- a/lib/Chat/Parser/SystemMessage.php
+++ b/lib/Chat/Parser/SystemMessage.php
@@ -351,9 +351,7 @@ protected function parseMessage(Message $chatMessage): void {
 			$parsedMessage = $this->l->t('{actor} invited {federated_user}');
 			if ($currentUserIsActor) {
 				$parsedMessage = $this->l->t('You invited {federated_user}');
-				if (isset($parsedParameters['federated_user']['server'], $parsedParameters['actor']['server'])
-					&& $parsedParameters['federated_user']['id'] === $parsedParameters['actor']['id']
-					&& $parsedParameters['federated_user']['server'] === $parsedParameters['actor']['server']) {
+				if ($this->isFederatedUserThemselvesActor($parsedParameters['federated_user'], $parsedParameters['actor'])) {
 					$parsedMessage = $this->l->t('You accepted the invitation');
 				}
 			} elseif ($this->isCurrentParticipantChangedUser($currentActorType, $currentActorId, $parsedParameters['federated_user'])) {
@@ -363,9 +361,7 @@ protected function parseMessage(Message $chatMessage): void {
 				}
 			} elseif ($cliIsActor) {
 				$parsedMessage = $this->l->t('An administrator invited {federated_user}');
-			} elseif (isset($parsedParameters['federated_user']['server'], $parsedParameters['actor']['server'])
-				&& $parsedParameters['federated_user']['id'] === $parsedParameters['actor']['id']
-				&& $parsedParameters['federated_user']['server'] === $parsedParameters['actor']['server']) {
+			} elseif ($this->isFederatedUserThemselvesActor($parsedParameters['federated_user'], $parsedParameters['actor'])) {
 				$parsedMessage = $this->l->t('{federated_user} accepted the invitation');
 			}
 		} elseif ($message === 'federated_user_removed') {
@@ -373,6 +369,9 @@ protected function parseMessage(Message $chatMessage): void {
 			$parsedMessage = $this->l->t('{actor} removed {federated_user}');
 			if ($currentUserIsActor) {
 				$parsedMessage = $this->l->t('You removed {federated_user}');
+				if ($this->isFederatedUserThemselvesActor($parsedParameters['federated_user'], $parsedParameters['actor'])) {
+					$parsedMessage = $this->l->t('You declined the invitation');
+				}
 			} elseif ($this->isCurrentParticipantChangedUser($currentActorType, $currentActorId, $parsedParameters['federated_user'])) {
 				$parsedMessage = $this->l->t('{actor} removed you');
 				if ($cliIsActor) {
@@ -380,9 +379,7 @@ protected function parseMessage(Message $chatMessage): void {
 				}
 			} elseif ($cliIsActor) {
 				$parsedMessage = $this->l->t('An administrator removed {federated_user}');
-			} elseif (isset($parsedParameters['federated_user']['server'], $parsedParameters['actor']['server'])
-				&& $parsedParameters['federated_user']['id'] === $parsedParameters['actor']['id']
-				&& $parsedParameters['federated_user']['server'] === $parsedParameters['actor']['server']) {
+			} elseif ($this->isFederatedUserThemselvesActor($parsedParameters['federated_user'], $parsedParameters['actor'])) {
 				$parsedMessage = $this->l->t('{federated_user} declined the invitation');
 			}
 		} elseif ($message === 'group_added') {
@@ -857,7 +854,13 @@ protected function isCurrentParticipantChangedUser(?string $currentActorType, ?s
 				&& $this->currentFederatedUserDetails['server'] === $parameter['server'];
 		}
 
-		return $currentActorType === Attendee::ACTOR_USERS && $parameter['type'] === 'user' && $currentActorId === $parameter['id'];
+		return $currentActorType === Attendee::ACTOR_USERS && $parameter['type'] === 'user' && $currentActorId === $parameter['id'] && empty($parameter['server']);
+	}
+
+	protected function isFederatedUserThemselvesActor(array $federated, array $actor): bool {
+		return isset($federated['server'], $actor['server'])
+			&& $federated['id'] === $actor['id']
+			&& $federated['server'] === $actor['server'];
 	}
 
 	protected function getActorFromComment(Room $room, IComment $comment): array {
diff --git a/tests/integration/features/federation/chat.feature b/tests/integration/features/federation/chat.feature
index f30b94e0b70..5550308477d 100644
--- a/tests/integration/features/federation/chat.feature
+++ b/tests/integration/features/federation/chat.feature
@@ -158,7 +158,7 @@ Feature: federation/chat
       | LOCAL::room | room | 2    | LOCAL        | room        |
     Then user "participant1" is participant of the following unordered rooms (v4)
       | id          | name | type | remoteServer | remoteToken | lastMessage |
-      | room        | room | 2    |              |             | {actor} invited you |
+      | room        | room | 2    |              |             | {federated_user} accepted the invitation |
       | LOCAL::room | room | 2    | LOCAL        | room        | {federated_user} accepted the invitation |
     And user "participant1" sends message "Message 1" to room "room" with 201
     Then user "participant1" is participant of the following unordered rooms (v4)
diff --git a/tests/php/Chat/Parser/SystemMessageTest.php b/tests/php/Chat/Parser/SystemMessageTest.php
index f6149b1535b..57797c64e6a 100644
--- a/tests/php/Chat/Parser/SystemMessageTest.php
+++ b/tests/php/Chat/Parser/SystemMessageTest.php
@@ -23,6 +23,7 @@
 use OCA\Talk\Share\Helper\FilesMetadataCache;
 use OCA\Talk\Share\RoomShareProvider;
 use OCP\Comments\IComment;
+use OCP\Federation\ICloudId;
 use OCP\Federation\ICloudIdManager;
 use OCP\Files\Folder;
 use OCP\Files\InvalidPathException;
@@ -431,18 +432,52 @@ public static function dataParseMessage(): array {
 				'The shared location is malformed',
 				[],
 			],
+			['federated_user_added', ['federated_user' => 'actor@federated.tld'], 'actor',
+				'You invited {federated_user}',
+				['actor' => ['id' => 'actor', 'type' => 'user'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+			],
+			['federated_user_added', ['federated_user' => 'actor@federated.tld'], 'user',
+				'{actor} invited {federated_user}',
+				['actor' => ['id' => 'actor', 'type' => 'user'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+			],
+			['federated_user_added', ['federated_user' => 'actor@federated.tld'], 'fed::actor@federated.tld',
+				'{actor} invited you',
+				['actor' => ['id' => 'actor', 'type' => 'user'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+			],
+			['federated_user_added', ['federated_user' => 'actor@federated.tld'], 'fed::actor@federated.tld',
+				'You accepted the invitation',
+				['actor' => ['id' => 'actor', 'type' => 'user', 'server' => 'federated.tld'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+				$federatedActor = true,
+			],
+			['federated_user_removed', ['federated_user' => 'actor@federated.tld'], 'actor',
+				'You removed {federated_user}',
+				['actor' => ['id' => 'actor', 'type' => 'user'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+			],
+			['federated_user_removed', ['federated_user' => 'actor@federated.tld'], 'user',
+				'{actor} removed {federated_user}',
+				['actor' => ['id' => 'actor', 'type' => 'user'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+			],
+			['federated_user_removed', ['federated_user' => 'actor@federated.tld'], 'fed::actor@federated.tld',
+				'{actor} removed you',
+				['actor' => ['id' => 'actor', 'type' => 'user'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+			],
+			['federated_user_removed', ['federated_user' => 'actor@federated.tld'], 'fed::actor@federated.tld',
+				'You declined the invitation',
+				['actor' => ['id' => 'actor', 'type' => 'user', 'server' => 'federated.tld'], 'federated_user' => ['type' => 'user', 'id' => 'actor', 'server' => 'federated.tld']],
+				$federatedActor = true,
+			],
 		];
 	}
 
 	/**
 	 * @dataProvider dataParseMessage
 	 */
-	public function testParseMessage(string $message, array $parameters, ?string $recipientId, string $expectedMessage, array $expectedParameters): void {
+	public function testParseMessage(string $message, array $parameters, ?string $recipientId, string $expectedMessage, array $expectedParameters, bool $federatedActor = false): void {
 		/** @var Participant&MockObject $participant */
 		$participant = $this->createMock(Participant::class);
 		if ($recipientId === null) {
 			$participant = null;
-		} elseif ($recipientId && strpos($recipientId, 'guest::') !== false) {
+		} elseif ($recipientId && str_starts_with($recipientId, 'guest::')) {
 			$attendee = Attendee::fromRow([
 				'actor_type' => 'guests',
 				'actor_id' => substr($recipientId, strlen('guest::')),
@@ -459,6 +494,25 @@ public function testParseMessage(string $message, array $parameters, ?string $re
 			$participant->expects($this->any())
 				->method('getSession')
 				->willReturn($session);
+		} elseif ($recipientId && str_starts_with($recipientId, 'fed::')) {
+			$attendee = Attendee::fromRow([
+				'actor_type' => 'federated_users',
+				'actor_id' => substr($recipientId, strlen('fed::')),
+			]);
+			$session = Session::fromRow([
+				'session_id' => substr($recipientId, strlen('fed::')),
+			]);
+			$participant->method('isGuest')
+				->willReturn(false);
+			$participant->method('getAttendee')
+				->willReturn($attendee);
+			$participant->method('getSession')
+				->willReturn($session);
+
+			$this->federationAuthenticator->method('isFederationRequest')
+				->willReturn(true);
+			$this->federationAuthenticator->method('getCloudId')
+				->willReturn(substr($recipientId, strlen('fed::')));
 		} else {
 			$participant->expects($this->atLeastOnce())
 				->method('isGuest')
@@ -478,11 +532,16 @@ public function testParseMessage(string $message, array $parameters, ?string $re
 
 		/** @var IComment&MockObject $comment */
 		$comment = $this->createMock(IComment::class);
-		if ($recipientId && strpos($recipientId, 'guest::') !== false) {
+		if ($recipientId && str_starts_with($recipientId, 'guest::')) {
 			$comment->method('getActorType')
 				->willReturn('guests');
 			$comment->method('getActorId')
 				->willReturn(substr($recipientId, strlen('guest::')));
+		} elseif ($recipientId && str_starts_with($recipientId, 'fed::')) {
+			$comment->method('getActorType')
+				->willReturn('federated_users');
+			$comment->method('getActorId')
+				->willReturn(substr($recipientId, strlen('fed::')));
 		} else {
 			$comment->method('getActorType')
 				->willReturn('users');
@@ -490,18 +549,42 @@ public function testParseMessage(string $message, array $parameters, ?string $re
 				->willReturn($recipientId);
 		}
 
+		$this->cloudIdManager->method('resolveCloudId')
+			->willReturnCallback(function (string $id): ICloudId {
+				[$user, $remote] = explode('@', $id);
+				$cloudId = $this->createMock(ICloudId::class);
+				$cloudId->method('getUser')
+					->willReturn($user);
+				$cloudId->method('getRemote')
+					->willReturn($remote);
+				$cloudId->method('getDisplayId')
+					->willReturn($id);
+				return $cloudId;
+			});
+
 		/** @var Room&MockObject $room */
 		$room = $this->createMock(Room::class);
 
-		$parser = $this->getParser(['getActorFromComment', 'getUser', 'getGroup', 'getGuest', 'parseCall', 'getFileFromShare']);
+		$parser = $this->getParser(['getActorFromComment', 'getUser', 'getRemoteUser', 'getGroup', 'getGuest', 'parseCall', 'getFileFromShare']);
 		$parser->expects($this->once())
 			->method('getActorFromComment')
 			->with($room, $comment)
-			->willReturn(['id' => 'actor', 'type' => 'user']);
+			->willReturnCallback(function () use ($federatedActor): array {
+				if ($federatedActor) {
+					return ['id' => 'actor', 'type' => 'user', 'server' => 'federated.tld'];
+				}
+				return ['id' => 'actor', 'type' => 'user'];
+			});
 		$parser->expects($this->any())
 			->method('getUser')
 			->with($parameters['user'] ?? 'user')
 			->willReturn(['id' => $parameters['user'] ?? 'user', 'type' => 'user']);
+		$parser->method('getRemoteUser')
+			->with($room, $parameters['federated_user'] ?? 'federated_user@federation.tld')
+			->willReturnCallback(function (Room $room, string $id): array {
+				[$user, $remote] = explode('@', $id);
+				return ['type' => 'user', 'id' => $user, 'server' => $remote];
+			});
 		$parser->expects($this->any())
 			->method('getGroup')
 			->with($parameters['group'] ?? 'group')
@@ -679,7 +762,7 @@ public function testGetFileFromShareForGuestWithBlurhash(): void {
 		$node->expects($this->once())
 			->method('getPermissions')
 			->willReturn(27);
-	
+
 		$share = $this->createMock(IShare::class);
 		$share->expects($this->once())
 			->method('getNode')
@@ -687,24 +770,24 @@ public function testGetFileFromShareForGuestWithBlurhash(): void {
 		$share->expects($this->once())
 			->method('getToken')
 			->willReturn('token');
-	
+
 		$this->shareProvider->expects($this->once())
 			->method('getShareById')
 			->with('23')
 			->willReturn($share);
-	
+
 		$this->url->expects($this->once())
 			->method('linkToRouteAbsolute')
 			->with('files_sharing.sharecontroller.showShare', [
 				'token' => 'token',
 			])
 			->willReturn('absolute-link');
-	
+
 		$this->previewManager->expects($this->once())
 			->method('isAvailable')
 			->with($node)
 			->willReturn(true);
-	
+
 		$this->filesMetadataCache->expects($this->once())
 			->method('getImageMetadataForFileId')
 			->with(54)
@@ -713,11 +796,11 @@ public function testGetFileFromShareForGuestWithBlurhash(): void {
 				'height' => 4567,
 				'blurhash' => 'LEHV9uae2yk8pyo0adR*.7kCMdnj'
 			]);
-	
+
 		$participant = $this->createMock(Participant::class);
-	
+
 		$parser = $this->getParser();
-		
+
 		$this->assertSame([
 			'type' => 'file',
 			'id' => '54',