diff --git a/TODO b/TODO
index 7b21eab..5d871ee 100644
--- a/TODO
+++ b/TODO
@@ -25,3 +25,4 @@
  - move uploading of files from release() to flush() because the return value of release is ignored and because the calling close() returns before release() finishes (problem: zero byte files are not allowed at the remote)
  - create a Debian package
  - call folder/get_content in a loop until more_chunks=no because folder/get_content only returns 100 items (or up to 1000 as given by the chunk_size parameter)
+ - proper versioning of the directory cache