diff --git a/core/attributedef.class.inc.php b/core/attributedef.class.inc.php
index 95553ff6f..d6717f95f 100644
--- a/core/attributedef.class.inc.php
+++ b/core/attributedef.class.inc.php
@@ -1510,11 +1510,33 @@ class AttributeLinkedSet extends AttributeDefinition
 		return $this->GetOptional('tracking_level', MetaModel::GetConfig()->Get('tracking_level_linked_set_default'));
 	}
 
+	/**
+	 * @deprecated 3.1.0 N°5563 this attribute is no longer used
+	 * @return string see LINKSET_EDITMODE_* constants
+	 */
 	public function GetEditMode()
 	{
 		return $this->GetOptional('edit_mode', LINKSET_EDITMODE_ACTIONS);
 	}
 
+	/**
+	 * @return string see LINKSET_RELATIONTYPE_* constants
+	 * @since 3.1.0 N°5563
+	 */
+	public function GetRelationType()
+	{
+		return $this->GetOptional('relation_type', LINKSET_RELATIONTYPE_LINK);
+	}
+
+	/**
+	 * @return boolean
+	 * @since 3.1.0 N°5563
+	 */
+	public function GetReadOnly()
+	{
+		return $this->GetOptional('read_only', false);
+	}
+
 	public function GetLinkedClass()
 	{
 		return $this->Get('linked_class');
@@ -2289,6 +2311,15 @@ class AttributeLinkedSetIndirect extends AttributeLinkedSet
 		return $this->GetOptional("duplicates", false);
 	} // The same object may be linked several times... or not...
 
+	/**
+	 * @return boolean
+	 * @since 3.1.0 N°5563
+	 */
+	public function GetReadOnly()
+	{
+		return $this->GetOptional('read_only', false);
+	}
+
 	public function GetTrackingLevel()
 	{
 		return $this->GetOptional('tracking_level',