diff --git a/VersionedMap.cpp b/VersionedMap.cpp
index 7b05150..0305112 100644
--- a/VersionedMap.cpp
+++ b/VersionedMap.cpp
@@ -946,6 +946,8 @@ VersionedMap::Iterator &VersionedMap::Iterator::operator--() {
     return *this;
   }
 
+  // TODO support decrementing end
+
   do {
     const auto &entry = *impl->map->mm.base[impl->finger.backNode()].entry;
     impl->map->move<std::memory_order_acquire>(impl->finger, impl->version,