diff --git a/src/Model/Contact.php b/src/Model/Contact.php
index ab8a7db8c..12cba0c08 100644
--- a/src/Model/Contact.php
+++ b/src/Model/Contact.php
@@ -38,7 +38,6 @@ use Friendica\Network\HTTPException;
 use Friendica\Network\Probe;
 use Friendica\Protocol\Activity;
 use Friendica\Protocol\ActivityPub;
-use Friendica\Protocol\DFRN;
 use Friendica\Protocol\Diaspora;
 use Friendica\Protocol\OStatus;
 use Friendica\Protocol\Salmon;
diff --git a/src/Model/Conversation.php b/src/Model/Conversation.php
index aa2faca50..a485ac2d9 100644
--- a/src/Model/Conversation.php
+++ b/src/Model/Conversation.php
@@ -38,7 +38,7 @@ class Conversation
 	const PARCEL_SALMON             = 3;
 	const PARCEL_FEED               = 4; // Deprecated
 	const PARCEL_SPLIT_CONVERSATION = 6;
-	const PARCEL_LEGACY_DFRN        = 7; // Deprecated
+	const PARCEL_LEGACY_DFRN        = 7; // @deprecated since version 2021.09
 	const PARCEL_DIASPORA_DFRN      = 8;
 	const PARCEL_LOCAL_DFRN         = 9;
 	const PARCEL_DIRECT             = 10;
diff --git a/src/Model/Post/DeliveryData.php b/src/Model/Post/DeliveryData.php
index 5c7fdd4d3..df1a22ff4 100644
--- a/src/Model/Post/DeliveryData.php
+++ b/src/Model/Post/DeliveryData.php
@@ -41,7 +41,7 @@ class DeliveryData
 
 	const ACTIVITYPUB = 1;
 	const DFRN = 2;
-	const LEGACY_DFRN = 3;
+	const LEGACY_DFRN = 3; // @deprecated since version 2021.09
 	const DIASPORA = 4;
 	const OSTATUS = 5;
 	const MAIL = 6;