diff --git a/main/inc/lib/usermanager.lib.php b/main/inc/lib/usermanager.lib.php
index 18898ccb34..5f8a6a18d2 100644
--- a/main/inc/lib/usermanager.lib.php
+++ b/main/inc/lib/usermanager.lib.php
@@ -2065,95 +2065,7 @@ class UserManager
         $row = Database::fetch_array($res, 'ASSOC');
         return $row['id'];
     }
-
-    /**
-     * Subscribes users to the given session and optionally (default) unsubscribes previous users
-     * @param	int		Session ID
-     * @param	array	List of user IDs
-     * @param	bool	Whether to unsubscribe existing users (true, default) or not (false)
-     * @return	void	Nothing, or false on error
-     */
-    public static function suscribe_users_to_session($id_session, $UserList, $empty_users = true) {
-
-    	if ($id_session != strval(intval($id_session))) return false;
-    	foreach ($UserList as $intUser) {
-    		if ($intUser != strval(intval($intUser))) return false;
-    	}
-    	$tbl_session_rel_course				= Database::get_main_table(TABLE_MAIN_SESSION_COURSE);
-		$tbl_session_rel_course_rel_user	= Database::get_main_table(TABLE_MAIN_SESSION_COURSE_USER);
-    	$tbl_session_rel_user = Database::get_main_table(TABLE_MAIN_SESSION_USER);
-    	$tbl_session						= Database::get_main_table(TABLE_MAIN_SESSION);
-    	$sql = "SELECT id_user FROM $tbl_session_rel_user WHERE id_session='$id_session'";
-		$result = Database::query($sql, __FILE__, __LINE__);
-		$existingUsers = array();
-		while($row = Database::fetch_array($result)) {
-			$existingUsers[] = $row['id_user'];
-		}
-		$sql = "SELECT course_code FROM $tbl_session_rel_course WHERE id_session='$id_session'";
-		$result = Database::query($sql, __FILE__, __LINE__);
-
-		$CourseList = array();
-
-		while($row = Database::fetch_array($result)) {
-			$CourseList[] = $row['course_code'];
-		}
-
-		foreach ($CourseList as $enreg_course) {
-			// for each course in the session
-			$nbr_users = 0;
-            $enreg_course = Database::escape_string($enreg_course);
-			// delete existing users
-			if ($empty_users !== false) {
-				foreach ($existingUsers as $existing_user) {
-					if(!in_array($existing_user, $UserList)) {
-						$sql = "DELETE FROM $tbl_session_rel_course_rel_user WHERE id_session='$id_session' AND course_code='$enreg_course' AND id_user='$existing_user'";
-						Database::query($sql, __FILE__, __LINE__);
-
-						if (Database::affected_rows()) {
-							$nbr_users--;
-						}
-					}
-				}
-			}
-			// insert new users into session_rel_course_rel_user and ignore if they already exist
-			foreach ($UserList as $enreg_user) {
-				if (!in_array($enreg_user, $existingUsers)) {
-                    $enreg_user = Database::escape_string($enreg_user);
-					$insert_sql = "INSERT IGNORE INTO $tbl_session_rel_course_rel_user(id_session,course_code,id_user) VALUES('$id_session','$enreg_course','$enreg_user')";
-					Database::query($insert_sql, __FILE__, __LINE__);
-
-					if (Database::affected_rows()) {
-						$nbr_users++;
-					}
-				}
-			}
-			// count users in this session-course relation
-			$sql = "SELECT COUNT(id_user) as nbUsers FROM $tbl_session_rel_course_rel_user WHERE id_session='$id_session' AND course_code='$enreg_course'";
-			$rs = Database::query($sql, __FILE__, __LINE__);
-			list($nbr_users) = Database::fetch_array($rs);
-			// update the session-course relation to add the users total
-			$update_sql = "UPDATE $tbl_session_rel_course SET nbr_users=$nbr_users WHERE id_session='$id_session' AND course_code='$enreg_course'";
-			Database::query($update_sql, __FILE__, __LINE__);
-		}
-		// delete users from the session
-		if ($empty_users !== false) {
-			Database::query("DELETE FROM $tbl_session_rel_user WHERE id_session = $id_session", __FILE__, __LINE__);
-		}
-		// insert missing users into session
-		$nbr_users = 0;
-		foreach ($UserList as $enreg_user) {
-            $enreg_user = Database::escape_string($enreg_user);
-			$nbr_users++;
-			$insert_sql = "INSERT IGNORE INTO $tbl_session_rel_user(id_session, id_user) VALUES('$id_session','$enreg_user')";
-			Database::query($insert_sql, __FILE__, __LINE__);
-
-		}
-		// update number of users in the session
-		$nbr_users = count($UserList);
-		$update_sql = "UPDATE $tbl_session SET nbr_users= $nbr_users WHERE id='$id_session' ";
-		Database::query($update_sql, __FILE__, __LINE__);
-    }
-
+    
     /**
      * Checks if a user_id is platform admin
      * @param   int user ID