diff --git a/TODO.md b/TODO.md
index 9f4d6d5..0650dfa 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,6 +1,7 @@
 ## v0.6.0
 - [ ] rewrite "open file" function
 - [ ] fix typos
+- [ ] change app extension to **.cnp**
 
 ## v1.0.0
 - [ ] add documentation