diff --git a/TODO b/TODO
index 922c2241..ab51c01e 100644
--- a/TODO
+++ b/TODO
@@ -25,6 +25,7 @@ Version 1.5.0:
 * Bus simulator interface.
 * Implement ecrt_master_slave() in kernel space.
 * Rename phy-commands to register commands.
+* Check for ioctl() interface version.
 
 Future issues: