diff --git a/TODO.md b/TODO.md
index 238e7b2..9fcf87a 100644
--- a/TODO.md
+++ b/TODO.md
@@ -6,3 +6,5 @@
 - Check for TODOs
 - Check types.
 - Switch to CBOR format.
+- Verify uniqueness before adding data.
+- Allow indexes to be NIL.